NRI/OCI (Overseas Citizen of India) are not eligible to obtain Aadhaar as per the Aadhaar Act and hence are fully exempted to produce Aadhaar for any verification... NRI/OCI need not verify their bank account or SIM or PAN with Aadhaar. If required, they may inform the service provider(s) that they being NRI/OCI are exempted from Aadhaar verification,"

2)Aadhaar number will be mandatory for filing I-T returns and for obtaining a Permanent Account Number for resident Indian citizens .This essentially means that you will require an Aadhaar card for all income tax-related transactions and you will need to link your Aadhaar number with your PAN card.

As foreigner you are not eligible to obtain Aadhar card 

IT returns have to be filed

Pan and aadhar need to be linked for the same

Please check the aadhar website for obtaining aadhar card. Its self explanatory and pretty straight forward and quick to get it

There are various agencies authorised by government for issuing Aadhar

Sir your daughter is not eligible for adhaar so for her in filing of returns Adhaar is not required. 

Refer the section here 

Insertion of new section 139AA.

56. After section 139A of the Income-tax Act, the following section shall be inserted, namely:—

'139AA. Quoting of Aadhaar number.—(1) Every person who is eligible to obtain Aadhaar number shall, on or after the 1st day of July, 2017, quote Aadhaar number—

(i)

in the application form for allotment of permanent account number;

(ii)

in the return of income:

Provided that where the person does not possess the Aadhaar Number, the Enrolment ID of Aadhaar application form issued to him at the time of enrolment shall be quoted in the application for permanent account number or, as the case may be, in the return of income furnished by him.

(2) Every person who has been allotted permanent account number as on the 1st day of July, 2017, and who is eligible to obtain Aadhaar number, shall intimate his Aadhaar number to such authority in such form and manner as may be prescribed, on or before a date to be notified by the Central Government in the Official Gazette:

Provided that in case of failure to intimate the Aadhaar number, the permanent account number allotted to the person shall be deemed to be invalid and the other provisions of this Act shall apply, as if the person had not applied for allotment of permanent account number.

(3) The provisions of this section shall not apply to such person or class or classes of persons or any State or part of any State, as may be notified by the Central Government in this behalf, in the Official Gazette.

A foreigner cannot get the Adhaar card .

Overseas citizen of India (OCI) and Person of Indian Origin (PCI) are also eligible to take aadhaar cards.

How to obtain aadhaar cards in the above case:

Visit Pre-enrolment portal, submit your demographic information.

Find nearest enrolment centre which you are comfortable to visit and book an appointment. 

If adhar is compulsory you can apply for the same. But there is no such compulsion who hasn't applied due to procedures and protocols

The Aadhaar Act, 2016 states, "Every resident shall be entitled to obtain an aadhaar number by submitting his demographic information and biometric information by undergoing the process of enrolment.

The Act further defines residency as, "An individual who has resided in India for a period or periods amounting in all to 182 days or more in the 12 months immediately preceding the date of application for enrolment. in layman terms, it can be said that if you are applying for Aadhaar today, you have to go back one year from the date of application and assess if you have spent more than 182 days in India.

This means that it does not matter whether you are an NRI or foreign national, if you have stayed in India for more than 182 days, you will be eligible to apply for Aadhaar.

However, the Act does not mention whether the date of arrival or departure is taken into consideration and/or a half day is taken into consideration while calculating minimum number of days required to stay in India.

One should not confuse Aadhaar residency definition stated above with the one mentioned in the income tax laws. The Income Tax Act defines an individual as a resident if in a financial year (1 April - 31 March), he has stayed in India for more than 182 days. On the other hand, under the Aadhaar Act, there are no specific dates defining a year.

The Aadhaar Act has clarified that even if you're holding an Aadhaar or applied for one it does not mean that you have received Indian citizenship.

Aadhaar is a 12-digit identification number issued to an individual after the receipt of demographic information such as address, date of birth and biometric information such as iris scan, finger prints etc.

It is a random number which has no relation to any personal details of the person.

Aadhaar is slowly becoming mandatory for a number of things e.g. doing banking transactions above Rs 50,000, getting benefits under government social security, subsidy schemes etc.

Section 139AA of the Income Tax Act states that every person who is eligible to receive Aadhaar number must quote the same while filing his income tax return. It further states that every person who is having PAN and is eligible to obtain Aadhaar or already has one must link the two to avoid PAN being invalid from a date to be notified by the government.

However, CBDT in its notification dated May 11, 2017 has exempted certain categories of individuals provided they do not hold Aadhaar and haven't applied for one. These are:

(i) Non - Resident Indians (NRI) as per Income Tax Laws
(ii) Not a citizen of India
(iii) Age more than 80 years or more at any time during the tax year
(iv) Residents of states of Assam, Meghalaya and Jammu & Kashmir

An individual is not under the purview of section 139AA if he or she is not a resident as per Aadhaar Act.

If your residency status changes in a particular tax year say, from NRI to Resident, then you will be required to quote Aadhaar number for filing tax returns.

The Supreme Court order regarding linkage of PAN and Aadhaar provides relief only to those who have PAN but not Aadhaar.

However, if you are going to file income tax return after July 01, 2017 then you are required to quote your aadhaar number (except for those exempted as mentioned above) which will inevitably require you to link your PAN with Aadhaar.

Regards 

Procedure for getting an Aadhar card for a foreigner?

She will have to stay in India for 180 days in the twelve months immediately preceding the date of application for enrollment;

Linking of aadhar to PAN in respect of NRI or OCI or foreign citizen is not mandatory because they are not given aadhar card.

Hence she may claim refund based on her IT returns. 

If any NRI or a Foreigner wish to apply for the AADHAAR card, they have to be physically present at any of the AADHAAR card center in India. You can apply at any of the open AADHAAR card center near your location in India. 

It has also become mandatory to link your Aadhaar with your existing PAN even if you don't file your ITR. ... This means that it does not matter whether you are an NRI or foreign national, if you have stayed in India for more than 182 days, you willbe eligible to apply for Aadhaar,