While you are adding your MX records, you should add the SPF record for sending from the Google servers.
What is a SPF Record? The SPF record is the Sender Policy Framework which helps prevent spammers from sending unauthorized emails from your domain. This type of spamming is called spoofing. Spoofing is a common unauthorized use of email so some email servers require SPF. If you don’t set up SPF for your domain, messages sent from your domain might bounce or might be marked as spam by some email hosts.
The SPF record is a TXT record in your DNS. To configure your DNS with the new SPF record you must have access to your domain DNS.
We’ll cover that separately and today we will assume you already have access and are ready to update the SPF record.
Values for G Suite SPF record
|Name/Host/Alias||Time to Live (TTL*)||Record Type||Value/Answer/Destination|
|@ or leave blank||3600||TXT||v=spf1 include:_spf.google.com ~all|
Note: Some domain hosts use different labels for the name and value fields, and some hosts also require the TXT value to be in ” “. (ie. “v=spf1 include:_spf.google.com ~all”)
Check your SPF record with the G Suite Toolbox.
For more information you can refer the Google support page.
Next you should consider setting up DKIM.