aspect ratio or conversion

Creative Cloud is the desktop app you use to manage your Creative Cloud software. 

I suspect you're trying to use the wrong tools for such a large banner.  Adobe Express imposes a limit of 20 inches in either direction.  So that's not the right tool for this project.

Photoshop CC can handle large images. 

Step 1: Create a new document

Go to File > New (Ctrl + N) and enter the required height, width and resolution for your final project as directed by print professional.  See screenshot.

Step 2: Import your artwork.

Go to File > Place Embedded. 

Select image and hit OK.

Use the transform Tool (Ctrl + T), click & drag handles to resize image to fit your canvas.

Save file (Ctrl + S) as  Banner3x4.psd.

If your print professional wants another type of file, go to File > SaveAs or SaveCopy in whatever file type is recommended -- JPG, PNG, TIFF, etc...

Hope that helps.

is this an indesign question?

Hi Brenda,

Thank you for reaching out to us. Could you please let me know the application you use to crop the banner you created in Adobe Creative Cloud? 

We are here to help you, it's just we need more information to investigate.

Regards,

Neelam