Can you put a line in a column chart at the norm? For example a project should be finished within 21 days. Can i when i have a chart, with the amount of days a project is finsihed, draw a horizontal line at the value 21?
Yes, it's called a reference line. You can add those on the Presentation tab under Reference Lines. You can also use variables or expressions to calculate the value for the reference line so you're not limited to a fixed number.