Is it okey to file separately if we are married because my husband is in Federal Prison

[coqueret]

But I did support him while he has been in Federal prison.

[TomD8]

You have the choice of filing MFJ or MFS despite the fact that your husband is incarcerated.  For most married couples, filing MFJ results in a lower total tax bill.

[Critter-3]

"support" is immaterial for a joint return ... so if he agrees to file jointly that is usually the best option even if he has little to no income.   If you did NOT  live together at any time the last 6 months of 2021 AND you have qualifying dependents then you may have the option to file Head of Household if you do pay more then 1/2 of the household expenses AND he will not agree to file a joint return. 

[NCperson]

@coqueret - filing MFS is going to be the worst option if you are eligible for EITC, so choose wisely!

[Mike9241]

his being in prison probably means he had no substantial income. so filing jointly, if he agrees, will give you the benefit of joint rates. also, some credits can not be claimed, if eligible, unless you file jointly. there are other limitations when married but filing separately.