By 'senior tax form', are you referring to IRS form 1040-SR tax return?
TurboTax will generate IRS form 1040-SR if the taxpayer is age 65 or above. There is no extra charge or discount for using IRS form 1040-SR.
The IRS created a version of Form 1040 that uses larger print and includes a standard deduction table directly on the for so that seniors can quickly look up their standard deduction amounts. IRS Form 1040-SR uses the same line items and instructions as the standard Form 1040.
Anyone age 65 or older can opt to use IRS Form 1040-SR instead of Form 1040. There are no other caveats that come with using this form. For example, you are not forced to take the standard deduction if you choose to file with Form 1040-SR.
See also here.