You will have to get married under the provisions of special Marriage Act. Since the legal age for marriage in India for girls is 18 years and for boys, 21 years, the same rule extends to marriage with a foreign national.
Any couple wishing to avail the fruits of this Act is required to issue a notice in writing to the “Marriage Officer” of the district where at least one of the parties to the marriage has been residing for the last thirty days. The marriage is generally scheduled within three months from the date of issue of notice. The notice so received will be published in the office of the Marriage Officer by displaying it in a conspicuous place. A copy of the same must also be attached to a “Marriage Notice Book,” which could be inspected by anyone.
Any objections to the marriage, with respect to age, capacity to consent, incest, etc, may be addressed to the Marriage Officer within 30 days of the publication of the notice. In case of any objections, the Marriage Officer is mandated to conduct an inquiry into its validity within a window of 30 days, during which the marriage cannot be solemnized. If the Marriage Officer discovers that the objection is valid and decides against the marriage of the concerned parties, the bride or groom may appeal to the district court within thirty days of such refusal. If all the concerned objections are dealt with, the bride, groom, and any three witnesses need to sign a declaration in the presence of the Marriage Officer, who would then countersign it. In the absence of any objections, the marriage will be solemnized upon the cessation of the objection period.
The following documents would be required:
Birth certificates (for age proof)
A valid visa of more than thirty days for the foreign national
A single-status affidavit signed by both parties. In case one of the parties has married previously, the Divorce Decree (for divorcees) or Certificate of Death (for widowed) is necessary.
Address proof and passport size photographs.
Adequate documentary evidence of 30-day residence in India.
A ‘no-objection’ letter.