AD adds background upon export

[BARBAKANE]

I'm creating a logo for my IG posts. I created a new document with a transparent background, added the logo and lettering, then saved it. (The logo is black and white...white meaning "white" and not a shade of grey.)  Upon exporting in jpg format to transfer to my phone, AD added the background. There is no flood erase tool in AD, (interesting why it's not there), so I tried doing the same thing in APhoto, and it adds the background. Also the invert function doesn't work. THere are numerous posts about it, but when I try to invert, the parts that are supposed to be white are a medium grey color, not white. I'm hoping the community can explain what I'm doing wrong, and if there is a way to fix it that's not a 15 step process. Invert should mean invert, not maybe invert then do 3 adjustment layers, bake a cake, jump thru a few flaming hoops while juggling chainsaws and dancing on one foot. I really don't want to fire up my windows XP machine and do this in Photoshop CS4, but I will if needed. Below is the "inverted" logo. The grey areas should by stark white, so they should up on photos with a dark background.THanks in advance.

 

[Ray S.]

Hi BARBAKANE,

jpg don't support transparency, you should use png for that purpose. For "whitening" the light greys you can use a "Treshold"-adjustment.

 

[R C-R]

13 hours ago, BARBAKANE said:

Also the invert function doesn't work.

What specific invert function in which app are you talking about (there are several)? What kind of object(s) are you trying to invert?