Its like the cassette catches when i spin in both directions . how can i fix this ?

everything is in decay, take it to your local bike shop and get them to service the freehub, likely cost about 10-30 quid depending if it needs new bits or buy a wheel.

£10-30 sounds optimistic if a bike shop is to service it. (It is here anyway)
Look for some how to videos on YouTube- it isn’t rocket science.
You probably just need to clean/oil your pawl springs.

Yep needs some love! Either diy or bike shop also depending on the hub may need some parts

Also worth checking that you haven’t got something wrapped around between the wheel and cassette, or your plastic spoke protector (if fitted) hasn’t moved and jammed it up. It wouldn’t be the first time a seized freehub has been fixed that way, doubt it’ll be the last either.

What hub is it?

have you done anything to the cassette/freehub (particularly taken it off) since it was last working properly ?

If it’s a Hope hub, check the seal behind the free hub is fully pressed in.

The hub is a “Bontrager sealed bearing”

No i have not done anything to the cassette/freehub .

By the way , thanks to all of you for helping me out 🙂

If it’s a Hope hub, check the seal behind the free hub is fully pressed in.

Yep, I made this mistake until I saw one of the Hope servicing videos.

The hub is a “Bontrager sealed bearing”

A lot of the more basic Bontrager sealed hubs use a sealed unit freehub.
Take it to a Trek dealer who will be able to find out exactly which one it is and get one for you.
To be fair some of them can be a right arse to fit as well. I’d pay the shop to do it.
(Well, if I were you I would, I’m expected to be able to do it as it’s my job…)