For Enabling to developer Mode In Redmi Note 7 :

1: Go to Setting.

2: Click to „About phone” option.

3: Press 7 times to „MIUI version” option.

now you will see a Toast message „now you are developer”.

=> Now you should install to Mi PC Suite from this .

1: Install the pc suite with connected your redmi.

2: Now go on Permission in setting and click „install via USB”.

=>For Enabling USB Debugging :

1: Open Settings > Additional settings > Developer options.

2: Firstly enable to developer options then go below and find USB Debugging and enable it.

3: When your pc suite open then again repeat disable and enable to USB Debugging