It would be great to have a repeating table control like in Infopath so that users can add multiple entries and submit them altogether. Also we should be able to do calculations based on rows , for example if I'm adding 3 expenses, I should be able to calculate the total and etc.
This nothing new but an exisitng feature in Infopath.
Thank you for your feedback! Much work is being done to facilitate form based controls. We will keep you updated as the work progresses.
In the meantime, you should already be able to sum rows. Please see article links below which should address requirement example (sum of expenses).
reference:
https://powerapps.microsoft.com/en-us/tutorials/working-with-tables/
webinar on formulas including a sample of your example:
https://info.microsoft.com/US-EAD-WBNR-FY17-03Mar-14-GettingStartedwithPowerAppsFormulas300770_01Reg...
Thank you,
Audrie