There are a lot of mobile apps available from SAP. You can find those in all the app stores like google play, apple store etc. There is a app store for SAP too,https://store.sap.com/sap/cpa/ui/resources/store/html/Solutions.html?pcntry=US&sap-language=EN&catID=MOB
SAP Business One - Android-Apps auf Google Play
You should have the prerequisites to use these apps. You have option to run the app without connecting to backends too.
Midhun VP