… if you want to test or troubleshoot your mobile webpage or browser app it’s quite tricky from desktop – mobile webapplication deliver content based on the browsers user agent – there are severals browser plugins to switch the agent – but all major browser offer a build in feature to change the behaviour
google chrome
in settings > more tools > developer tools (Crtl + Shift + I) below network conditions your able to switch user agent – e.g. search at google to display

microsoft edge and internet explorer
F12 developer tools (press F12) > Emulation opens an onboard user agent switcher

mozilla firefox
webpage is loaded in same way an iPad would do – type about:config in addressbar, search for useragent and create a new entry
string: general.useragent.override
value: Mozilla/5.0(iPad; CPU OS 6_0 like Mac OS X) AppleWebKit/536.26(KHTML, like Gecko) Version/6.0 Mobile/10A5355d Safari/8536.25

macOS safari
enable in settings > advanced the option show develop menu in menu bar

iOS devices
since iOS13 / iPadOS – safari browser of the apple tablet can switch between mobile and desktop presentation of a webpage, as shown in the video below
android devices
install e.g. Rocket Browser to test the behavoir of other user agents, in Settings > General Settings is it possible to change the user agent – developed android webapps can define an own user agent with java code webview.getSettings().setUserAgentString(MyString);
test your Browser features here and see what’s your browser capable of
