Mega backdoor roth contributions

I contributed to my employer's 401K account that support mega backdoor roth (Fidelity's in-plan conversion). My W2 form's box 14 showed Other and the contribution amount as AFTAX.

Should I expect any 1099 or tax related forms for this mega backdoor contribution? Is this the same as my 401K or Traditional IRA contributions?

Does these contributions lower my taxes for 2025 in any way? How to correctly report this contribution?

Thanks.