When I am going uphill and I am putting a lot of pressure into pedaling I am hearing a ‘clicking’ in the gears. Any ideas how this can be fixed?

There are lots of YouTube videos on derailleur adjustment.

Are you struggling to pedal as you go up the hill? Using all your leg muscle to try and climb at low rpm will usually put more strain on the chain and drive train causing it to make clicks, popping sounds and other noise. Especially if shifting gears when at low rpm's and using lots of leg muscle.

Shift to a gear ratio that keeps your cadence higher when going up the hill.

Worn cassette?
Just put on a new chain and it was fine before?
If you use your larger cogs a lot climbing they may have more wear that was not noticed before a new chain.

Post in the proper section, which isn't GD. Bicycle mechanics is what you're looking for.

Perhaps you could provide more information about your bike, make, model, age. It is very difficult to diagnose a problem without knowing what sort of bike you have

It's also very hard to diagnose a problem from a vague description. Clicking noise could be anything, chain slip, misaligned derailleur, bad bottom bracket bearings, etc. If we had a video of the bike in action with the clicking noise it would help.

I don't normally chime in with "me, too" posts, but in this case perhaps reiteration is justified. You give too little information in your post, you'll get suggestions that are, justifiably, all over the place. It could be the chain ticking the spokes if the limit screw is not adjusted properly. It could be you have to feather the rear derailleur. It could be worn chain/cassette. It could be that it's not the gears at all - pedals? bottom bracket? bars? saddle? Etc., etc.

One post with no follow-up. Problem must not have been that concerning.