These are the solutions I worked on, based on your suggestions.

I still don't know what would be the best approach that helps:

1. User to intuit the expected input (format, average characters).
2. User to understand the labels (self-explanatory) (tooltips provided for difficult questions)
3. The form to be as readable as possible (help eye tracking)
4. The form to be beautiful, consistent.

Please refer to the most suitable option, according to the needs above. Thanks!

These are the solutions I worked on, based on your suggestions.

I still don't know what option will derive on the best experience, a solution that helps:

1. Users to intuit the expected input (format, average characters).
2. Users to understand the labels (self-explanatory) (tooltips provided for difficult questions)
3. The form to be as readable as possible (help eye tracking)
4. The form to be beautiful, consistent.

Please refer to the most suitable option, according to the needs above. Thanks!