Install preferred solutions to gain added features and functionality for Microsoft Dynamics CRM Online.
The list of available solutions varies. Some solutions like Office 365 groups for Dynamics CRM are freely available and visible by default. Trials for some solutions are gated and will only be visible if you go through Settings > Dynamics Marketplace or appsource.microsoft.com and sign up for the solutions. If you buy a new service subscription through Office Commerce, any associated solution installer also becomes visible in the Solutionstab after that purchase is recognized by the provisioning system.
Install a preferred solution
Sign in to https://portal.office.com with your Global administrator or CRM System Administrator credentials.
Click Admin centers > CRM
Click the Instances tab, and then select the instance to add the solution to.
Click Solutions.
Select the solution you want to install and click Install.
Proceed through Terms of service to accept the terms.
The status for the solution changes to Installation pending.
The status for the solution will change to Installed when the solution is ready.
Delete a preferred solution
Make sure that you have the System Administrator or System Customizer security role or equivalent permissions.
Sign in to CRM.
Click Settings > Solutions.
Select a solution and click Delete.
Source: Technet Microsoft