I am not able to see Fitness + App on my fitness app

iPhone>Settings>right under your name should be the 3 month offer.

Make sure that both your watch and iPhone are fully updated to Watch OS 7.2 and IOS 14.3

You would see the Apple Fitness + on the settings app on your iPhone

If they are both up to date

Then first force restart your iPhone by whatever method your version calls for.  As soon as you see the Apple logo force restart your watch by holding in the crown and side button for 10 seconds till you see the Apple logo then release.  Log into your iPhone and wait for your watch to boot, then log into it.

Failing that click the link "get support" on the upper right side of this page.

You need to have ios14.3 on the phone and WatchOS7.2 on the watch and be in a region that supports fitness+.

That region isn't supported;

These are the supported countries;

Australia, Canada, Ireland, New Zealand, the UK, and the US.