Jinja Template Integration in Custom Doctype

I have created a custom doctype within my custom application in Frappe, which includes a docfield named message_template of the text editor type. This doctype is integrated with Telegram, allowing me to send messages to users upon submission. The message content is derived from the message_template.

I would like to implement Jinja template functionality within the message_template. Specifically, I want to write content using Jinja syntax, allowing me to pull values from various doctypes based on unique identifiers. For example, if I am using an employee record, I would like to access data associated with the employee_id and retrieve information from related doctypes using Jinja templates.

Could anyone please guide me on how to achieve this integration?