Einstein Activity Capture is a great step into bringing salesrep activity data (email and calendar events) into Salesforce. By default Einstein Activity Capture pulls in emails and calendar events and associates them with EXISTING Salesforce Contacts and Accounts.
Note, Einstein Activity
The Salesforce Chrome Extension is an Addin for Gmail and is available for Free with your Sales Cloud License.
Salesforce Inbox is an additional charge and commonly referred to as Salesforce Inbox Premium.
Both of these solutions from Salesforce are designed as a Productivity Assistant for Salesreps. Which include things like Salesforce Account/Contact lookup, Search, and also the ability to push Events and Emails to Salesforce. Both are