Can't open p12 file inside my application

I need to open p12 file from other iOS applications to import private key to my application. My app is set up to be able to open nay file with following plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>CFBundleDocumentTypes</key>
	<array>
		<dict>
			<key>CFBundleTypeName</key>
			<string>Files</string>
			<key>LSHandlerRank</key>
			<string>Default</string>
			<key>LSItemContentTypes</key>
			<array>
				<string>public.item</string>
				<string>public.data</string>
				<string>public.content</string>
			</array>
		</dict>
	</array>
</dict>
</plist>

But my don't appear in share dialog from Files or Mail app for example. There are however other third party apps that can accept this file. Some of them use Share extension which I don't have, but some of them don't have it as far as I can understand. At least they don't present any UI and open apps directly.

Also I've tried to specify com.rsa.pkcs-12 UTI directly but it didn't help. Also noticed that *.crt files have similar behaviour.

Am I missing something about this specific file type?