1. First, download Masquerade module and place it to sites/all/modules folder.
2. Install that module from Admin , Modules
3. Set "Masquerade" block from Admin, Structure, Block.
4. Set permission. we are able to set up "Masquerade" module in 2 ways
- move to Admin, People
- Edit any user profile. Specify usernames what we must switch from edited user account in comma separated.
- go to Admin , People, Permission.
- Set following permissions to specific role
After implement above settings when user login following block will appear in page.
When we specify any other user in textbox and press Go button block appear as follow: