I want to focus on creating printable templates in the future and I really like creating them with photoshop. When I viewed a few existing examples on the graphicriver marketplace, I saw that many were using Adobe Illustrator and a few Adobe InDesign. My question is what the difference is. If I have a mockup available I could also just create the layout and paste it on the mock up. Wouldn’t it be the exact same thing?
Your response to this will be welcome! 
My opinion is that InDesign is excellent program for print templates.
WHY:
It’s optimized for pirint industry. Excellent font options. Stuning precision.
Illustration is best for Illustrations and logos. InDesign for print templates. Photoshop is a universal program, but is excellent for photo manipulation and web design.
Thank you for the answer. But in your opinion, could photoshop be used instead of illustrator or InDesign? Because as far as I have seen, I have been doing the same things, such as logos or printable designs, with photoshop. Also may I know what kind of special features InDesign has compared to Photoshop? 
noscraft said
Thank you for the answer. But in your opinion, could photoshop be used instead of illustrator or InDesign? Because as far as I have seen, I have been doing the same things, such as logos or printable designs, with photoshop. Also may I know what kind of special features InDesign has compared to Photoshop?![]()
You can use Photoshop for print design ofc.
I am using it! 
But also I am using InDesign when create something like book design, letter forms, etc.
You have better font/text control, better grids, alignments, etc. 
I am not pro, but I know that InDesign have a lot of better options for print design than photoshop.
Don’t you think there is a reason about why a multinational corporation would create 3 different softwares if only photoshop is the best for everything? 
photoshop is for photo manipulation
illustrator for illustration -> vector shapes
indesign for layout and print stuff -> just imagine how would you make a template with automatic page numeration in ps?
