Mail Merge requires a Premium or Enterprise level plan.
Mail Merge is available using our legacy add-in within Outlook ExchangeAccount managers and Account Owners can control access to mail merge by going to https://app.yesware.com/account/policies
Managers can decide to limit their team from using Yesware Mail Merge by setting the max number of recipients allowed per mail merge, from 0 to our max of 200. Changing this setting to 0 will make the Mail Merge option within Gmail disappear completely. This can be set as an account wide policy or per member.