Are you refer to the Create/Photo Book feature in the Elements Organizer? That is a feature associated with Photoshop Elements Editor and its Elements Organizer? Do you have Photoshop Elements as well as Premiere Elements?
What version of the program?
What computer operating system?
I have road tested your problem on Elements Organizer 14/Photoshop Elements 14 Windows 7 64 bit, and can type with and without upper case.
What font, what size...
Have you used Reset Tool or Reset Tools to try to overcome the problem?
If this is a Photoshop Elements/Elements Organizer issue without involvement of Premiere Elements, then it would be to your advantage to re-post your question in the Adobe Photoshop Elements Forum to take advantage of the specialized expertise there. Some how your thread got posted in the Adobe Premiere Elements Forum (video editing).
Please consider and give more details. Then we can decide what needs to be done to move on in your Elements project.
I'm using Photoshop Elements 12, the other half of Adobe Premier Elements 12. I do not see any reset tools button. I am running Windows 10 Pro 64 bit. Also, I have been able to insert text in both upper and lower case before. Don't have a clue as to what I might have done to change the case to all upper case. I posted in the premier area because that is the name of the Adobe program I purchased. I will re-post my request in the photoshop elements section. Thanks for your comments. Have used the full photoshop program for years, and then got away from the business. This problem never appeared before in the full program.
Elements Organizer 12/12.1 Create/Photo Book will take you into the Photoshop Elements Editor workspace after you have selected your theme.
Click on the Text Tool in the Toolbox to bring up the Options Panel at the bottom of the workspace. Look to the top right of that Options Panel. Click on the tiny triangle to get the drop down list with Reset Tool, Reset All Tools.
If this worked before, the resetting of the tools may be the answer for your situation. Let us see.