PGAdmin Edit data
Right-click on your table, select View Data/View All Rows (or one of the variants). That window will let you edit the data. Then press F6 to save changes (with thanks to leverglowh for pointing that out).
Right-click on your table, select View/Edit Data -> All Rows:
Then there is an icon in the top bar, looking like a table with an arrow pointing down (the icon on the right of the screenshot below):
The icon is gray but works nevertheless.