I'll share some steps for you to utilize the template you've created in your invoice, Diana.
Upon checking in our system, there's no current issue regarding with invoice template. To make your chosen style your default, you can do it within the Custom form styles window. I'll show you how:
Step 1: Create a New style
Go to the Gear icon located at the upper right corner and choose Custom Form Styles.
Click the New Style dropdown and choose the type of transaction you'd like to make.
Modify your sales forms according to your preferences.
Once done, click Done.
Step 2: Set your selected forms as your default.
Click the Edit dropdown located under the Action column.
Tap the Make default option.
Afterward, find the template you've created earlier. There should be indificated as Dedault within the From Type column.
If issue perssist, you can use any recommended browser or an incignito. This way, you'll be able to set up your styles.