I think my phone was installed the monitor hided software that my phone was monitored. How to find the software and deleted?

1.

See the Apple articles below: 

Checklist: If you want to make sure no one else can see your location

Checklist: If you want to make sure no one else can see your location - Apple Support

Control app tracking permissions on iPhone

Control app tracking permissions on iPhone – Apple Support (UK)

If an app asks to track your activity

If an app asks to track your activity - Apple Support

See also ->  Share your screen in FaceTime on your iPhone or iPad

Share your screen in FaceTime on your iPhone or iPad - Apple Support

  ⤵️

Everyone can see what's on your screen until you stop sharing, but they can't control anything on your device. If you get any notifications while sharing your screen, others won't be able to see them.

When you're sharing your screen, others won't be able to see content that requires a subscription, a free trial, or a purchase or rental to view. 

2.

See -> Check your Apple ID device list to see where you're signed in

Check your Apple ID device list to see where you're signed in - Apple Support

-> if you see devices that don't belong to you, delete from your account.

3.

I think my phone was installed the hided monitor software that my phone was monitored. How to find the software and deleted?

Not sure which App you have installed, use App Library to search that app you are looking for, see this Apple article:

Organize the Home Screen and App Library on your iPhone

Organize the Home Screen and App Library on your iPhone - Apple Support           

4.

If purchased the app from App Store, unhide your purchase, see -> Hide purchases from the App Store

Hide purchases from the App Store – Apple Support (UK)

-> scroll to Unhide apps on your iPhone, iPad or iPod touch.

5.

Read again -> Related Article -> If you think your Apple ID has been compromised

👉 If you completed the steps above and think your account might still be compromised, contact Apple Support.