Some Android devices use a default keyboard which doesn't provide a decimal point or coma.
Should you need to give quantities with decimals in your Job Report, Parts & Services or for Invoices and Quotes please download another keyboard through Google Play.

Here is a link towards the Gboard app: 
https://play.google.com/store/apps/details?id=com.google.android.inputmethod.latin&hl

Once you have downloaded the app go to "Settings", in "Language and input" (1), then to "Default keyboard" (2) and select your new keyboard (3).