Why this happens
When you create a match, you select a competition first. The team dropdowns only show teams that are assigned to that competition. If you've created a team but it doesn't appear when creating a match, the team isn't assigned to the competition you selected.
How to fix it
Option 1: Edit the team and add the competition
1. Click Assets in the left sidebar
2. Select Clubs and Teams
3. Find and select the team that isn't appearing
4. Click on the Competitions section in the General tab
5. A dropdown will appear with all available competitions
6. Select the competition (you can select one or multiple)
7. Click Save at the bottom of the screen
The team will now appear in the team dropdowns when creating a match under that competition.
Option 2: Create the team with the competition selected from the start
1. Click Assets > Clubs and Teams
2. Click Create a Club or Team > Create a Team
3. Select the competition in the team creation form
4. Fill out the remaining team details
5. Click Create Team
The team is immediately available for matches in that competition.
Important notes
* Teams must be assigned to a competition to appear in match creation
* You can assign a team to multiple competitions
* You need at least two teams assigned to a competition before you can create a match
* You can change a team's competition assignment even after matches have been created, but existing matches retain their original competition assignment