I created a set of buttons in oracle apex region but when I run the application its not arranged like the page items
why its not arranged and how I will arrange it to be one by one and space between buttons same space can you see the image please :
There are multiple options for buttons, pick which one suits you best.
However, each region has a number of pre-defined positions where you can put buttons too. There are less options for configuration in those other pre-defined positions.
Typically, for a large number of buttons like in your case, I'd use a region template of type "Buttons Container" and then set all button attributes to "Start New Row: No" and "New Column: No". This gives a layout like this:
--Update--
To edit button spacing, use the "template options" for the component template. In the screenshot below: navigate to button > Appearance > Template Options:
Edit template options:
Do this for each button. Usually the region template will have similar options, those can also be used.