I'm attaching... VS I attach... VS I attached...

[Polyester]

For this situation which one is correct? And why?(I knew the grammar is different, I would like to know the meaning differences,thank you!)

For seeks a job,
I'm attaching my CVs for your reference.

I attach my CVs for your reference.

I attached my CVs for your reference.

 

[GoesStation]

Numbers 1 and 2 are okay. I prefer the second. Number 3 doesn't work.