Somebody asks how most of your new patients found you, or which of them take blood thinners, and the answer is in a notebook, three intake forms and your memory. Patient fields give each of those facts a place on the patient, where you can read it, sort by it and filter the whole list on it.
Define the fields you need
Open Settings → Patients and add a field: give it a label and choose a type. The types are Free text (short), Free text (paragraph), Email, Yes / No, Single select, Multiple select, Date, Percentage and Number. Select fields take a list of options, and every field can carry a hint and a tooltip. A practice can have up to 30, and the page shows how many you have used.
Edits save as you make them. Renaming a field keeps every answer already recorded, because answers are stored against the field and not its label.
If you would rather not start from a blank page, Add starter fields at the top of the page drops in a ready-made set for referrals, insurance, safety flags, scheduling preferences or background.
Fill them in on the patient
Each field appears as a row on the patient's details card, under Last visit, showing a dash until there is an answer. Open the patient's menu and choose Edit details to fill them in: a Custom fields section lists every field with the right control for its type. Yes / No, select and date answers save the moment you choose them, and typed answers save when you click away. Fields are not on the New patient dialog, so add them after the patient exists.
Two people editing different fields at once will not overwrite each other, since each change is merged into what is already saved. Anyone on your team can fill them in, and the edit is written to the access log by record id only, never with the answer.
They become columns
Every patient field is a column in the patient roster. It starts hidden; turn it on in the Columns menu. Click its header to sort. Filters offer what suits the type: contains, equals and starts with for text; equals, greater and less than for numbers and percentages; is, is before and is after for dates; is and is any of for single and multiple selects. A Yes / No field filters on Yes or No, and every field offers is empty and is not empty, which is how you find the patients you never asked. Patients with no answer sort to the bottom either way.
Filter values stay in the page and never go into the address, since they can be clinical; only is empty and is not empty may appear there. To share a filtered list, save it as a view. If a field's type is changed later, answers that no longer fit the new type read as empty rather than breaking the list.
In and out with CSV
The patients export includes one column per field headed Patient field: followed by the label, plus a combined Custom fields column. Both are read back by the import wizard, which matches the headers for you, and re-importing a file never clears an answer the file does not mention. This works for the whole data export and for the Export selected as CSV bar on the roster.
What to know
The list is a fixed set of types: there is no repeating list, so something like a medication list is not available as a patient field yet, and a form question does not fill a patient field automatically.