I'm creating a logo and struggling with joining a shape to text. As you can see from the images. The text is 'MN.' And I am attempting to use a semi circle shape to join the letters. However, it cannot align perfectly. Any help on how to align it perfectly and join it with the text would be great thank you.
Convert your connecting path to a shape (Object > Expand, check "Stroke") then you can use the Smart Guides (⌘+U) or View > Snap To Point and drag the anchors until everything snaps.
Then you can select all objects and use the boolean operation Add to join the shapes.
Note: Following works only if m and n are strokes, not shapes (I would recommend not expanding your m and n objects if they were strokes initially, as it will help you design better. Later you can expand.).
There's a Control + J command in Illustrator. I think that can give you the result you want.
a) With selection tool, select (highlighted by rectangle) the two points you want to join
b) Press Control + J (Windows)
For the perfection:
c) Make sure smart guides are turned on in View > Smart Guides
d) It will help you to draw a circle (make stroke width equal to m or n's stroke) which will align perfectly with your m and n points
e) Make it semicircle using any suitable tool like Scissors (C) tool
f) Move it up and align
After joining, you might need to adjust the overall weight of the artwork again.
Edit: Workaround if m and n are text.
Create outlines from the text. Find the horizontal middle of the legs of the m or n. Take it as a reference for center and draw the circle snapping to the middle points (as discussed above). One thing you'll need to pay attention here is the circle you draw is a stroke, but m and n are expanded shapes. So you can't compare their widths. You'll have to make a rough idea by using a physical ruler or drawing small shapes and using it as a ruler.