Can we have button for Place Block instead of text.

It looks like you are using Basic as your Admin theme. I personally always use Seven or Adminimal for the admin interface. To customize this, you can go to "/appearance" and customize your administration theme at the bottom of the page.

Having said that, you are welcome to customize Basic for your administration theme but you would have to complete that work on your own. In any application, the goal of Basic is to provide developers a solid starting point when working with a custom design.

Please reach out if you have further questions.

Cheers, Leah

One way to maybe help fill in the gaps is look at setting seven/adminimal as a base theme and use basic to override the bits you want to change.