They won’t be notified that you blocked them, but they canfind out with a little detective work.
While they can mention your username in their posts, these mentions aren’t displayed in your Activity stream.
Here’s how to block another user:
Download and kick off the Instagram app on youriOSorAndroiddevice.

Find and load the profile of the user account you want to block.
TapMenu(three dots), located in the upper-right corner of the screen.
A confirmation box explains what happens when you block the account.

You’ll see a message that the account is blocked.
TapDismissto finish the process.
To unblock the account, return to its page, tapmenu, and then selectUnblock.

If the person has a private account, you’ll have to request to follow them again.
In the upper-right corner of the screen, tapMenu(three dots).
SelectBlock this userfrom the pop-up menu.

SelectDismissto complete the process.
To unblock the account, return to its page and selectUnblock.
FAQ
Todeactivate your Instagram account, access to Instagram on a web net online gate.

Select yourprofilepicture >Edit Profile> tapTemporarily disable my accountand follow the prompts.
Tochange your password, go to the log-in screen and tapForgot Password.
slide in your email address, phone number, or username and selectReset Password.

