My phone says that I have too much junk on my phone and it's going to shut down do you guys know of a good program or anything that I can download to get rid of it thank you

[rocksteady]

I dont know what type of phone you have android or IOS, but android Files app or similar should allow you to clean out junk. Also check Recycle Bin on app’s and clear content from that.
I would be careful using third party “cleanup” apps without confirming what they will remove. Some can be agressive and remove files that you want to keep.