Is that on macOS, Windows, or iPadOS? Or all? This one is complicated by the multiple platforms, but I know for macOS and Windows where I'm assuming the license question would come up the FileSets here;
https://fwkb.atlassian.net/wiki/spaces/KB/pages/4327902/TeamViewer+macOS+Client+Setup
https://fwkb.atlassian.net/wiki/spaces/KB/pages/4327890/TeamViewer+Windows+Client+Setup
Those will help you get the TeamViewer Host client on your machines and shouldn't ask about a license. The full version of TeamViewer that you'd want to run on your FileWave Admin machines would mention a license, but you can run it without a license. It'll not force you to have one and we've handled all the legality of it with TeamViewer.
In the case of iPadOS ( https://fwkb.atlassian.net/wiki/spaces/KB/pages/4327912/TeamViewer+iOS+iPadOS+Client+Setup ) it's just installing QuickSupport so I'm imaginging your question was about either your admin machine or your clients.