Host: https://YOUR_SUBDOMAIN.rest.marketingcloudapis.com POST /messaging/v1/messageDefinitionSends/dfa5ab87-1b0f-e211-b71b-9c8e9920e9fc/send Content-Type: application/json Authorization: Bearer YOUR_ACCESS_TOKEN

What is the SendID that is mentioned in the above given URL? How do we obtain that from SFMC?