We do not see Mexican peso in currency dropdown in ERP while creating quotations
Mexican peso is very much there in currencies. It must either not be enabled or it must be disabled for particular type or types of quotations.
If you cannot see it anywhere in the system, then it is most likely not enabled. Please go to accounting >> manage currencies and exchange rates. On top you will see the list of active currencies along with current exchange rates, auto-update settings and correction factors. At the bottom there is another list of inactive currencies. On the left side of each row (or inactive currency) there is a green color button to enable the currency. Please click that and the currency will be activated. After activation, it will show in the active currency list. You can edit properties and rules for all active currencies.
If the currency is already active, then it must be disabled for the type of quotation. Please go to sales >> manage >> quotation types and click on the edit button on the left side of the row for the quotation type that you are trying to create. There is a section where you specify currencies. If the section is blank that all active currencies show while creating the quotation of this particular type. If there is any currency or few currencies specified, then only that currency or those currencies will show. You can add MXN to this list.