You can send your resignation through email there is no hard and fast rule to send it in company portal

Dear client, 

It's important to follow the proper resignation procedures and ensure that your resignation is acknowledged by the company. If you fail to do so, the company may mark you as absconding, which can negatively impact your future employment prospects.

Since you do not want to log into the company's portal to submit your resignation, you could consider sending a formal resignation letter via email. This letter should include your name, position, and the date of your resignation, as well as a clear statement of your intention to resign from your position. It should also express gratitude for the opportunity and mention any positive experiences you had during your brief time with the company.

In the email, you should request that the company acknowledges your resignation and confirms that they have received it. You could also mention that you did not receive any company assets and that you did not mark your attendance in the company portal.

Make sure to keep a copy of the email and any response you receive from the company, as it may be useful in case of any future disputes. It's important to handle the situation professionally, as this will ensure that you maintain a positive relationship with the company, which could be beneficial in the future..

Dear client, 

If your offer letter explicitly states that you must raise your resignation through the company portal and that any other mode of resignation will not be considered, then it is important to follow this requirement in order to ensure that your resignation is accepted and processed by the company.

If you do not comply with the company's requirement for raising your resignation through the portal, it is possible that your resignation may not be considered as valid and you may be considered as absconding or may face other consequences.

Therefore, it is recommended that you follow the company's protocol and raise your resignation through the company portal as per the offer letter. If you face any issues in accessing the portal or have any concerns regarding the process, it is advisable to reach out to the company's HR department or your reporting manager for assistance.

Q-1.

Without a formal resignation your company cannot proceed further regarding your resignation. So company cannot act on your mail without formal resignation. You have no option but to formally submit your formal resignation resigning from your post. You have to take NOC or clearance from company regarding assets of company otherwise you will not be relieved. 

Q-2

Yes, hope so. It may be company policy. 

Even though you have not signed your attendance in the comp[any's portal, as you have accepted the employment offer and had signed the acceptance letter agreeing to the terms and conditions, you ill be termed to be an employee of the organisation and bound by the regulations of the company.

However since you have already tendered resignation through email, you can refer the same and send a letter by registered post confirming your last working date and stop attending the office beyond the stipulated working date.

If they treat as absconding, let them do it, because the 5 days experience certificate is not valid anywhere neither they may decide to recover the compensation for not serving the notice period.

Other than recovery of notice period compensation, they cannot take any other legal action even if they declare you to be an absconder.

Since you have not logged in to the company's portal ever since you joined the organisation, you need not be worried about the company's terms.

Let them declare you to have absconded, since you are not going to reflect this employment in your CV, you need not be very serious about this threat.

is not necessary to send resignation vide company portal 

resignation by email should suffice 

It is not necessary that resignation should be on company portal only

company has received your resignation 

You can send it vide email as you are scared to touch the company portal as stated by you. Ideally you can send it on company portal also

Why are you showing yourself ever in their employment. No attendance ever marked. Just send last mail to refuse to accept the employment and offer letter. No need to say resign.

Also disclaim to own any of the company assets.

- As per Specific Relief Act, if any employee quits before the notice period, the Employer can only recover the Notice pay, and the Company cannot force to serve the entire notice period.

- Further, the resignation decision is the employee’s decision, and the employer cannot sue for breach of contract, if the employee leaves without serving contractual notice. 

- Further, no employer can refused to return the original certificates or to issue relieving letter .If they are doing so, their act is illegal, unjustified and against the fundamental rights of the employee.

- Further, the employment bond with the negative covenant is valid and legally enforceable, if the parties agree with their free consent i.e. without force, coercion, undue influence, misrepresentation and mistake, but it is not enforceable, if it is either one sided, unconscionable or unreasonable

- Since, you have worked only 5 days then it come under the rule of probation , and no notice period will be applied therein. 

- Further, as you have already informed the company for your resignation through email , then it is not mandatory to follow the other rule of the company , The company cannot harm you for any reason.