How do I file this year with a boyfriend

[SweetieJean]

You cannot file Joint, since you are not married.  Did he live with you all of 2021?  How much was his 2021 income?

[VolvoGirl]

You each file Single unless you have a child and one of you qualifies as Head of Household.   If you lived together the WHOLE year one of you might be claimed as a dependent if they made less than $4,300 total income.

[Hal_Al]

You each file your own separate tax return using Single filing status.

But, if you're really asking about something else, you need to be more specific. For example, common questions are:
Can I claim my boy friend as a dependent?

We have a child, who gets to claim the child?

My boyfriend is a student, can I claim his tuition?

Can my boyfriend claim my child?