Trying to make letters of the Alphabet

[fred_dot_u]

I confirmed that I have Microgramma D Bold Extended typeface installed in my computer. I then started Fusion 360 and started a new sketch on the x/y plane. Selecting Create>Text and dragging out a rectangle, I was presented with the dialog box from which I chose the correct typeface. I typed in your text and set the height to 75 mm, then used E to extrude to 3 mm as per your message. All is good, but it's important to note that your requirement of 75 high and 75 wide is not valid. The letters are 75 mm high, but the width of the A is slightly greater than 114 mm. The attached zip file contains a Fusion 360 format file so you can adjust as you like as well as an STL file with the proportional typeface as noted above.