While combined trademarks (i.e. logo) in general display a higher level of distinctiveness in comparison to text forms alone, a particular emphasis needs to be put on the form of the logo in order to satisfy the distinctiveness requirement when it comes to trademark registration.
Please go through the examples of trademark logos below that display both high and low levels of distinctiveness.
Highly distinctive trademark logos (examples)
Creating distinctive character forms within the logo
Adding a separate graphical element in addition to the visualisation of the brand name
Low distinctiveness of trademark logos (examples)
Merely using a slightly non-conventional font to display the original descriptive brand name
Utilising colour schemes in an attempt to create a visual distinctiveness
Using generic shapes that are widely used across the given industry sector