Some members are having trouble downloading PDF files. Here is advice from Team App Support on how to overcome this issue

Unable to open PDF’s:
If you are unable to open content within various sections of your team’s app such as schedules, documents or newsletters, this may be because your device cannot open PDF files or because you have certain restrictions set in your device settings.

For convenience we display PDF’s in a web-view within the app, so your device may have restrictions in relation to viewing specific web content. Check your device’s privacy / website settings and select to allow all web content, or alternatively ensure www.teamapp.com is selected as one of your allowed domains.

Here are some other troubleshooting tips for your device:
Download the latest version of Team App via the App Store or Google Play.
Ensure you have the latest available version of your device’s operating system.
Download a free ‘PDF Viewer’ app from the App Store or Google Play, as you may not have the available software on your device to open PDF’s.
Delete and re-install Team App (you won’t lose any data or your teams doing this).
Ensure you have given Team App permissions to access files on your device.

Also, remember you can access PDF’s via the website version of your team’s app at www.teamapp.com.