Ease of Use/Understanding:
* Easy
* Simple
* Clear
* Straightforward
* Understandable
* Comprehensible
* User-friendly
Physical Access:
* Reachable
* Attainable
* Available
* Open
* Convenient
Social Access:
* Inclusive
* Open to all
* Welcoming
* Available to the public
For information:
* Obtainable
* Available
* Retrievable
For a person:
* Approachable
* Friendly
* Open
Please provide more context about how you're using the word "accessible" and I can give you a more precise synonym!