Add signing fields

Fields anchor a signer's input to a region of a page. Each field is associated with a signer and a field type (signature, initials, date, text, checkbox).

POST /v1/envelopes/{id}/fields

curl https://api.permissio.us/v1/envelopes/$ENV_ID/fields \
-H "Authorization: Bearer $PERMISSIO_KEY" \
-H "Content-Type: application/json" \
-d '{
  "signer_id": "sgn_01HZX9...",
  "type": "signature",
  "page": 1,
  "x": 120,
  "y": 640,
  "width": 220,
  "height": 48
}'

Coordinates are in PDF points (72 per inch), with the origin at the bottom-left of the page.