Apologies but I'm not 100% sure what you mean by this bit "specific emails with any kind of keywords so that this email can be used to create a ticket with correct data inside?".
Hopefully you can have your external application send mails to a specific mailbox. Then MailManager can be setup to create a specific type of process from this particular mailbox. It can also be configured to apply a specific template (default text) to the processes that get raised. You also create a mail mapping to map each part of the email message that you want to be stored in a specific attribute in Service Desk.
Apologies if I have mis-understood your requirement and I will be happy to try again if you can clarify further,
I think Waterb was reffering to something like specific key words within the message body would cause that part of text to go in a specific field on the incident.
So rather than the whole body of the message going into description, you might have something like the below:-
Description: this is the fault i am having
Urgency: Prevents me from working
This 1 field in the could then populate 3 different fields within the incident.
I seem to recall an ER was raised for this?
Ah I understand now thank you. No this isn't currently functionality I'm afraid. I have looked for an ER for this but this is the closest I could find:
You may decide to create a new enhancement unless you find a better match than this.