Hi @Anshu kumar,
thanks for pointing that out. However, I already enabled Automatically Copy TOTP after autofill option in the browser settings. As I don't know how Enpass tracks down TOTP inputs, it might be related to an Linux issue. As I found out TOTP autofill didn't work under stable Enpass 5 (on OS: elementaryOS 0.4.1 (Ubuntu 16.04), Browser: Firefox 62.0 & Automatically Copy TOTP after autofill option enabled), as well. So this isn't mainly an Enpass 6 issue. Sorry that I didn't test this beforehand. :-/
Kind regards ;-)