Changing the page size in MS Word is simple and allows users to adjust documents as needed. You can switch between sizes like A4, A3, A5, Letter, Legal, B4, B5, or set a custom size, depending on your document requirements.
Steps to follow:
Step 1: First, open MS-Word on your PC.
Step 2: Now, open the document or create a new one in which you want to perform this operation.

Step 3: Now, go to the "Layout" tab. (Shown in the below image and marked)

Step 4: Now, In the Page Layout tab, go to the "Page Setup" section. (Shown in the image below)

Step 5: Now, In Page Setup Section there is the option "Size". Click on the Size Button and select the size of your choice.

Step 6: Now, When we choose the More page size option in MS-Word, then a window will appear (as shown below) and we can customize the size of the page according to our choice.
So, the change of size from A4 to B5 is successful.
