Can I still e-file now if I don't have my 2018 return?

[Anonymous]

you need your 2018 adjusted gross income (line 7) from 2018.   you don't say why you don't have a copy, thereefore i can only offer you this suggestion.    register at IRS website and get a transcript of your 2018 return

https://www.irs.gov/individuals/get-transcript

if you can't get it you'll have to paper file (also state return, if required will have to be paper filed)