My HSA was overfunded by $80 but my employer is applying to 2019 how do I show that?

[BMcCalpin]

If your employer overcontributed to your HSA by $80 in 2018 and subsequently contacted the HSA custodian to retrieve the amount and then apply it to 2019, then your employer owes you a corrected W-2, which shows the code W amount reduced by $80. Otherwise, TurboTax will calculate an excess contribution for you and expect you to withdraw it, when, in fact, your employer already did.

Otherwise, I don't know what your employer means by "applying it to 2019".

Your employer might tell you that "we'll just add it to your 2019 W-2", but the paperwork that the IRS gets (copies of the W-2 and 5498-SA won't match). Ask the employer for a corrected W-2 - this will be copied to the IRS.