I got a new phone and my emails are going into a clients suspect file. What’s up?

There is no setting on your device that controls how someone else's device handles mail that you have sent them. That is something about how their device and mail is configured. They need to find that out on their device. Have them check with their email provider and how it handles junk mail.

Is this happening while you are on wi-fi or cellular data? The only thing I can think of is if their email is "seeing" something different about the mail. I'm guessing that your email address is in your contact card on their device? Otherwise, they are going to have to work that out with their provider. There is no setting on your end that you can use to change how their mail client handles their mail.