61disabled lady/on ssi/ssdi/ I want to claim my 9yr old ,service dog/ 3yrs homeless ,didn't give up my dog//I have had her all her life.she isn't cheap

Refer to IRS Publication 502 Medical and Dental Expenses.

    www.irs.gov/pub/irs-pdf/p502.pdf

Page 8 discusses Guide Dog or Other Service Animals.
A portion of such expenses are only deductible if you itemize deductions.

If SSI and SSDI is your only income then you do not even need to file a tax return.

I believe the statement "If SSI and SSDI is your only income then you do not even need to file a tax return" is not true in all cases.  It is probably true in most cases - but not all.  There are multiple situations where Social Security is your only income, but you may need or want to file a tax return.  Some of those situations are for lump sum distributions, or if you receive a large amount of Social Security income, or if you had taxes withheld - you may want to file to get a refund.  And yes, there are more such situations.

I suggest using the IRS Interactive Site to determine whether or not such payments are taxable

https://www.irs.gov/help/ita/are-my-social-security-or-railroad-retirement-tier-i-benefits-taxable

I further suggest using the IRS Interactive Site to determine whether or not filing a tax return if required.

https://www.irs.gov/help/ita/do-i-need-to-file-a-tax-return

For each of the above sites click the "Begin" button at the bottom of the screen.

SSI is not reported on a tax return.

If you had enough income for your disability benefits to be taxed, then you probably wouldn’t qualify for SSI anyways, as they are meant for low-income applicants.