SEP IRA accounts are individual accounts in the name of the employee. Check with the SEP IRA custodian for the custodian's procedure for the employer to open a SEP IRA account for the employee and for the employer to submit contributions. The account must be specifically established as a SEP IRA account, not an ordinary traditional IRA account.
The SEP IRA contribution will appear as a pension expense on the S corp's tax return, Form 1120S line 17. See the Instructions for Form 1120S: https://www.irs.gov/pub/irs-pdf/i1120s.pdf
