Reza Rad simplifies multiple selection:
This is a very short, simple article about how to have a multi-select slicer in Power BI. Power BI slicer is in fact multi-select by default, however, there is a very small option that if you set it, makes it even easier to use, let’s talk about it. If you want to learn more about Power BI, read the Power BI book from Rookie to Rock Star.
Click through to see how you can perform multi-selection by default, as well as an alternative setting.