Go to Settings > API Keys. Click "Create API Keys"
Copy the API Key you get.
Go to the Site Settings > Forms > SendGrid, enter your API Key into the field "SENDGRID API KEY", add the email and the domain the website will use after publishing and then click "Activate". There can be several domains.
Go back to the page with the form and open the menu of the "Content" block.
Check "Connected Services" and "SendGrid". Enter hints for the fields, the button text and message to display in the event of successful data capture.
Publish the page. The contact form is ready!
If anything fails to work, please make sure your page has the same address you entered in the form settings.