There is no "form" ... a statement is simply attached to the return and it is reflected in your bookkeeping records. The statement cannot be efiled when using the TT system.
Per the IRS :
Election to Capitalize Repair and Maintenance Costs
To reduce the difficulty with applying the facts and circumstances analysis to identify the tax treatment of costs and to recognize simpler administration by permitting you to follow financial accounting policies for federal tax purposes, the final tangibles regulations include an election to capitalize repair and maintenance expenses as improvements, if you treat such costs as capital expenditures for financial accounting purposes.
You may elect to treat repair and maintenance costs paid during the taxable year as amounts paid to improve property if you:
- Pay these amounts in carrying on a trade or business; and
- Treat these amounts as capital expenditures on your books and records regularly used in computing your income.
- Make the election to capitalize for each taxable year in which qualifying amounts are incurred by attaching a statement to your timely filed original federal tax return including extensions for the taxable year that the amounts are paid.
- If you make the election to capitalize repair and maintenance expenses, you must apply the election to all amounts paid for repair and maintenance that you treat as capital expenditures on your books and records in that taxable year. For more information see When and how do you make an election provided under the final tangibles regulations?
- An annual election is not a change in method of accounting. Therefore, you shouldn't file Form 3115, Application for Change in Method of Accounting, to make this election or to stop capitalizing repairs and maintenance costs for a subsequent year.
https://www.irs.gov/businesses/small-businesses-self-employed/tangible-property-final-regulations#El...
