There are 2 ways in which you can access additional Salesforce fields when logging an email to Salesforce:
1. Log Additional Fields to Salesforce When the Email is Opened on your Gmail
- If this is an inbound email, you would press the Log dropdown next to the email and then press Search and Select. For outbound emails, press the log dropdown and press Search and Select.
2. Select the Contact/Lead/Opportunity/etc. you want to attach the email to.
3. Press 'Review Selected Records & Options'
4. Fill out any of the fields that you need to and press 'Attach'
2. Log Additional Fields to Salesforce Right from the Compose Window
- Click "Compose" button in Gmail to begin composing an email
- Enter the recipient of the email (the email does not have to be logged to the recipient)
- Click on "Logging" to search and select the record you want to log the email to
- Click the down button found next to the record name that the email is being logged to and scroll down to enter the additional fields you'd like to edit!