How to let axis and tooltip show different number format
Tooltip is a very important function to let end user know more detail of a chart and keep chart clean. So we need simpler number format in chart and detailed number format in tooltip.
For example, in axis we wish numbers can be showed as K or M but in tooltip with full numbers.
Let us use Superstore datasource. Drag order Date to Rows and Sales to columns and we will get below chart:

Since it's a sales number, some users want axis show with "$", then we change axis format to make axis show as "$K", but tooltip also showed "$K':

We can duplicate Sales and rename it "Sales (Axis)", and change it's format to $K, then drag it to Columns to replace Sales, drage sales to detail and modify tooltip to only keep "Sales: <SUM(Sales)>".
Then we can get diffrent format for axis and tooltip:
