Issue #775
My share sheet and action extension not showing up in iOS 14, built-in Xcode 12.3. The solution is to restart test device, and it shows up again.
Also make sure your extension targets have the same version and build number, and same deployment target
<dict>
<key>NSExtensionAttributes</key>
<dict>
<key>NSExtensionActivationRule</key>
<dict>
<key>NSExtensionActivationDictionaryVersion</key>
<integer>2</integer>
<key>NSExtensionActivationSupportsText</key>
<true/>
<key>NSExtensionActivationSupportsWebURLWithMaxCount</key>
<integer>1</integer>
<key>NSExtensionActivationSupportsWebPageWithMaxCount</key>
<integer>1</integer>
</dict>
<key>NSExtensionJavaScriptPreprocessingFile</key>
<string>MyPreprocessor</string>
<key>NSExtensionActivationUsesStrictMatching</key>
<integer>2</integer>
</dict>