Hi Geraldo,

You can do this through XML-RPC by setting the correct values for the creation. I've made a proof of concept that shows the whole process to do it. You just have to get the right activity types and ids, which I didn't do in my example as I do not know where you want to link to:

import xmlrpclib

username = 'admin' # The Odoo user
pwd = 'admin' # The password of the Odoo user
dbname = 'v11' # The Odoo database

# OpenERP Common login Service proxy object 
sock_common = xmlrpclib.ServerProxy ('http://localhost:8069/xmlrpc/common')
uid = sock_common.login(dbname, username, pwd)

# replace localhost with the address of the server if it is not on the same server
# OpenERP Object manipulation service 
sock = xmlrpclib.ServerProxy('http://localhost:8069/xmlrpc/object')

activity_record = {
'activity_type_id': 1,
'res_id': 1,
'res_model_id': 1,
'date_deadline': '2018-08-30',
'user_id': 1,
'note': 'The activity message'

}

# Calling the remote ORM create method to create a record 
result = sock.execute(dbname, uid, pwd,'mail.activity', 'create', activity_record)
print('Inserted new activity! Id: ' + str(result))

Regards,

Yenthe