If you elected to defer income into a Roth plan with your employer, the amount will show in Box 12 depending on the type of plan the code can be AA, BB or EE.
However, this Roth account is not a Roth IRA. Enter amounts shown in box 12 of your W-2 only in box 12 of TurboTax's W-2 form, nowhere else in TurboTax.
Since you said Roth account and not on W2, believe this is a SEP. If so, follow these steps, Where do I enter my SEP IRA contributions?
Related links:
Designated Roth Accounts - Internal Revenue Service.
Ten Differences between a Roth IRA and a Designated Roth Account.
SEP contributions cannot be Roth contributions.
It's extremely common for people to think that a Roth account in an employer plan is a Roth IRA, but it can't be. A designated Roth account in an employer-provided retirement plan is a different kind of Roth account.
Roth contributions to an employer-provided retirement plan are reported with code AA, BB or EE in box 12 of the W-2 and are to be entered only in box 12 of TurboTax's W-2 form.
Employers can provide for deposit of part of your pay into a Roth IRA, but this is simply a convenience for you to make regular personal contributions to a Roth IRA and is not an employer-provided retirement plan. It's unlikely that the amount of personal contributions would appear anywhere on your W-2, but if it did, it would only be for your own information, perhaps in box 14.