Suitable is an adjective, and its main usages and fixed collocations are as follows:
1.*Basic Usage**:
Used to describe a person, something, or condition that is appropriate for a particular purpose or occasion.
Example: She is suitable for the job(She's fit for the job.) ）
It is followed by the preposition for to indicate a suitable object or purpose.
Example: This dress is suitable for a wedding(This dress is suitable for weddings.) ）
2.*Fixed collocation**:
suitable for something
It means "suitable for doing something" or "suitable for a certain occasion or use".
Example: The software is suitable for beginners(This software is suitable for beginners.) ）
suitable to do something
Less common, sometimes indicates behavioral appropriateness) is appropriate to do something.
Example: He was suitable to lead the team(He's fit to lead the team.) ）
3.*Other related expressions**:
be not suitable (for)
Indicates that it is not suitable.
Example: These shoes are not suitable for hiking(These shoes are not suitable for hiking.) ）
find something suitable
Find the right thing.
Example: I need to find a suitable apartment close to my workplace(I need to find a suitable apartment close to my place of work.) ）
In conclusion, when using suitable, the key is to understand what it means "suitable" and to choose the right preposition for the context and what follows.