Can i file taxes if i was a full time student but did not work?

Maybe, but probably not. You haven't provided enough information. How old are you? Where do you live? How do you support yourself. If support is from student loans, was there a co-signer?

What are you trying to get by filing a tax return?

The stimulus payment?  

Under the CARES Act, if you are claimed as a dependent, or CAN be claimed, on someone else’s return you cannot receive a stimulus check, in 2020.   If you qualified as a dependent for 2019, but will not be for 2020, you will most likely get it  in 2021, by filing a 2020 tax return. 

The education Credit? 

A full time unmarried student, under age 24, is only eligible for the refundable portion of the American Opportunity Credit if he supports himself by working. You cannot be supporting yourself on parental support, 529 plans or student loans & grants. You usually must have actually paid tuition, not had it paid by scholarships & grants.  It is usually best if the parent claims that credit.  You cannot claim a credit if you are, or can be, claimed as a dependent by someone else.

There are two types of dependents, "Qualifying Children"(QC) and standard ("Qualifying Relative" in IRS parlance even though they don't have to actually be related). There is no income limit for a QC but there is an age limit, student status, a relationship test and residence test. Only a QC qualifies a taxpayer for the Earned Income Credit and the Child Tax Credit. They are interrelated but the rules are different for each.

The support test is different for each type. The support test, for a QC, is only that the child didn't provide more than half his own support. The support test for a Qualifying Relative is that the taxpayer provided more than half the relative's support. 

See full rules at: https://turbotax.intuit.com/tax-tools/tax-tips/Family/Rules-for-Claiming-a-Dependent-on-Your-Tax-Return/INF12139.html