Legacy UI workflow

Can anyone please explain me how legacy UI works? means for updating data delete or adding how the post , get is working?

Did you get a chance to look at this? https://guide.openmrs.org/en/

Actually I added one new field in database for person registration and currently using legacy ui now I want to ad data on this field i can add using rest web service module but i am not able to find that on legacy ui module or how the controllers and database are connected. If you can help me it would be very helpful.

We generally do not recommend modifying core database tables. Did you take a look at person attributes on these pages? http://archive.flossmanuals.net/openmrs-guide/openmrs-information-model https://wiki.openmrs.org/display/docs/Managing+Person+Attribute+Types https://wiki.openmrs.org/display/docs/Person+Attribute+vs.+Observation