I'm wondering if i there is a measuring tool we can use on the phone devices to be able to measure drawings like electrical maps etc.
How would this work? Would the user have to have the tool on his computer to save the file with the capability to measure and will i be able to measure on using my phone?
The functionality of an desktop application and mobile application is very much different. You do not get access for all the tools that you can use through the desktop app because mobile device doesn't have all the compatible component to run those functions.
Measuring tool is one of them, this functionality is currently unavailable for the mobile app.
You can fill the feature request form regarding the same- Feature Request/Bug Report Form