When a record is deleted in CRM it cannot be restored in CRM using OOB functionality. The only option is to restore the environment to the previous back up which will revert all the changes made to the previous backed up version.
However, we can restore selected records using the Recycle bin plugin in XRM Toolbox (mush have admin privileges). Note that this requires the audit history is enabled on the table.
Download XRM Toolbox from the link.
Install the XRM toolbox and then install the Recycle bin plugin, connect it to the required environment by following the below steps.
Click on the Connect option on top left corner of the application.
Select new connection > Microsoft Login Control > Open Microsoft Login Control
Select the deployment type Office 365 and select the display list of available organizations and login with your credentials.
Select the environment which you want to restore the records and give a name and click finish.
Once the environment is connected, select the recycle bin tool from the list.
It should open the app as above. Click on the Load Entities and Users then Select the Entity you want to restore the data from and select the user. We can also choose the date range of the deleted records to make the search easier.
Once done click on the show deleted records which will show all the deleted records in the date range selected then select the records you wish to restore and select restore records, which will restore the records.
I noticed that sometimes the deleted records might load and throws the below error.
This error can be resolved by uninstalling the Recycle bin plugin and reinstalling it from GitHub code. Link to GitHub code.
Hope this helps!