What is the difference between CRM and helpdesk/ticketing system, when to use each?

Guys hi

As the title says i wonder what is the difference between CRM VS helpdesk/ticketing system and when to use each.

Details: We are small tour operator, 99% sales are coming online (ecommerce), and currently all communication (support and sales) goes through one email and is handled by one person. This set-up is obviously not right (often emails get lost, etc). So as i understand we should add help desk/ticking system (for which we love Zammad!). But when CRM is needed ? Is it one or another or do they often go hand in hand ?

if you want to more control and organize all in coming / outgoing inquiry support or sales zammad is the answer, but for CRM if im not mistaken is the customer relationship management… zammad can handle that i think not totally sure. customer details. records of customer tickets… inquiry etc… but theres alot of crm system…

tha k you