Can I get tax credit for post graduate tuition? If so how? I did not receive 1098from the school.

You MUST have a 1098-T (or an exception*) to claim an education credit or deduction.  Grad students are not eligible for the more generous American Opportunity Credit, but are eligible for the others.

In TurboTax (TT), enter at:

Federal Taxes Tab (Personal for H&B version)

Deductions & Credits

-Scroll down to:

--Education

  --Education Expenses

 To be eligible for the tuition credits or tuition & fees deduction, the course must be taken at "an eligible institution". The school should be able to tell you if it is an eligible educational institution. In general, an eligible educational institution is an accredited college, university, vocational school, or other postsecondary educational institution, including accredited, public, nonprofit, and proprietary (privately-owned, profit-making) postsecondary institutions. Additionally, in order to be an eligible educational institution, the school must be eligible to participate in a student aid program administered by the Department of Education. If they issue a 1098-T they are probably an eligible institution.

Enter your school at the link below, to see if it's on the dept. of education list.

https://fafsa.ed.gov/FAFSA/app/schoolSearch?locale=en_EN

*Form 1098-T requirement. To be eligible to claim the tuition
and fees deduction, American opportunity credit, or the lifetime
earning credit, the law requires a taxpayer (or a dependent) to
have received a Form 1098-T from an eligible educational
institution.
However, a taxpayer may claim one of these education
benefits if the student doesn’t receive a Form 1098-T because
the student’s educational institution isn’t required to send a
Form 1098-T to the student under existing rules (for example, if
the student is a nonresident alien, has qualified education
expenses paid entirely with scholarships, or has qualified
education expenses paid under a formal billing arrangement). If a
student’s educational institution isn’t required to provide a Form
1098-T to the student, a taxpayer may claim one of these
education benefits without a Form 1098-T if the taxpayer
otherwise qualifies, can demonstrate that the taxpayer (or a
dependent) was enrolled at an eligible educational institution,
and can substantiate the payment of qualified tuition and related
expenses.