If you elect to expense up to $5,000 of expenses, you would debit expenses credit cash (or A/P).
For the amount (if any) over $5,000 that may be amortizable, you would debit an asset account and credit cash. Then when you amortize the costs, you would debit amortization expense and credit accumulated amortization.
There are some costs that may not be expensed or amortized...these deal with the corporate stock itself. You would debit an asset account, such as intangibles or stock cost, and credit cash.
These cost do not increase your basis in the stock you purchased or received in exchange for contributions of cash or other property.
See also
https://www.irs.gov/pub/irs-pdf/i1120.pdf
https://www.irs.gov/pub/irs-pdf/p542.pdf
**Disclaimer: Effort has been made to offer correct information; but due to the discussion forum limitations, the poster disclaims any legal responsibility for the accuracy of the poster's response**
