Positive v. Evap line

I keep hearing about evap lines, and I’m not sure what they really are or how to tell if you have one.

The picture below was taken after 4 minutes and I am 8-11 DPO (app says 8 but I’m pretty sure I ovulated early this cycle making me 11). The line is super super faint. Posting anonymous because I know people here and don’t want anyone I know to know if it’s positive.