There are no forms to report a Roth contribution. The financial institution, which is the trustee of your Roth IRA, will send you information on the amount in your Roth IRA. They will also send the information to the Internal Revenue Service. Use Form 8606 (PDF), Nondeductible IRAs, if you made a nondeductible contribution to a traditional IRA; converted from a traditional IRA, a SEP, or Simple IRA to a Roth IRA, received a distribution from a traditional IRA, a SEP, or a Simple IRA and made nondeductible contributions to a traditional IRA, or received a distribution from a Roth or IRA.

References:

• Publication 590, Individual Retirement Arrangements (IRAs)
• Form 8606 (PDF), Nondeductible IRAs and Coverdell ESAs
• Tax Topic 428, Roth IRA distributions