Like in Dynamics 365, you see a total number of records under a view. And you want similar in a Canvas PowerApp too. 
Here’s a simple tip to do so –
CountRows() method
It’s pretty simple. Using CountRows(source) method, you can get the count of records in the Source. In this case, it’s the CDS entity Accounts.
To flourish how I display the count, I use the Concatenate() method and…
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Count of total CDS records returned in a Canvas Power App connection [Quick Tip] – D365 Demystified
Quick Tip to get the count of records retrieved by the connector.
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