Acquisition of Indian citizenship can be through three ways- naturalization, descent, and registration.

1. Naturalization:
This is the process through which a foreigner can acquire Indian citizenship. The Citizenship Act, 1955 provides for the following conditions to be fulfilled for naturalization:
- The applicant must have resided in India for at least 12 years.
- The applicant must have stayed in India for at least 11 years out of the 14 years preceding the 12-year period.
- The applicant must be of good character.
- The applicant must have an adequate knowledge of any one of the languages prescribed in the Constitution.

2. Descent:
A person can acquire Indian citizenship by descent if he/she is born to at least one Indian parent. However, the following conditions must be met:
- The parent must be an Indian citizen at the time of the child's birth.
- If the child is born outside India, the parent must register the birth within one year of the child's birth.

3. Registration:
This is a process of acquiring citizenship by applying for it. The Citizenship Act, 1955 provides for the following categories of people who can apply for registration:
- A person of Indian origin who is ordinarily resident in India for seven years before applying for registration.
- A person of Indian origin who is residing outside India but has come on a visit to India and wants to extend his/her stay.
- A person who is married to an Indian citizen and has been residing in India for at least seven years before applying for registration.
- A minor child whose parents are Indian citizens.

Therefore, Indian citizenship can be acquired through naturalization, descent, and registration.