I. (Roman Numeral)
A.
1. Text
a.
i.
I wish to set the space between any of the symbols and the following text. and have the option to make it uniform.
If your question is about chapter numbering (formerly outline numbering), settings are in Tools → Chapter Numbering..., tabs Numbering and Position.
If you are talking about list numbering, bulleted or numbered, default settings are in Format → Bullets and Numbering... while specific settings are customized through modifying list styles Numbering x and List x, Numbering and Position tabs.
Selecting level “1-10” in both cases sets simultaneously for all levels.
If this answer helped you, please accept it by clicking the check mark 
to the left and, karma permitting, upvote it. If this resolves your problem, close the question, that will help other people with the same question.