Adding XY data on QGIS

Use the 'Add Delimeted Text' button (icon is a single quotation mark - near the top of the icons for adding layers on the left-hand side of a standard QGIS 3.16 interface). This can take a few text formats and, just like ArcGIS's tool, you can specify the x and y fields. You can also specify the delimiter if it is not a comma for instance.

If you would like add XY as coordinate of point, you can use Field calculator in Attribute table. There are calculate geometry functions. Or you can use XyTools Plugin to work with coordinate.