I had claimed my sister last year how do i claim my son this year

You can claim your son as a dependent on your return if he meets the Qualifying Child or Qualifying relative requirements:

Qualifying child

• They're related to you.
• They aren't claimed as a dependent by someone else.
• They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They're under the age of 19 (or 24 for full-time students).
  • No age limit for permanently and totally disabled children.
• They lived with you for more than half the year (exceptions apply).
• They didn't provide more than half of their own support for the year.

Qualifying relative

• They don't have to be related to you (despite the name).
• They aren't claimed as a dependent by someone else.
• They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They lived with you the entire year.
• They made less than $4,300 in 2020.
• You provided more than half of their financial support.

To claim your son :

1. Open or continue your return in TurboTax.
2. Select My Info in the left navigation.
3. Select the Add a dependent button if you need to add someone.