To the <Name of Embassy>:
I, <Full Name>, <citizenship> citizen with passport number <Passport No.>, would like to request a longer stay visa for <country>. Over the past two years I have been flying in and out of <region> as part of my work and assignments as <reason>, in addition to leisure trips as a culture and history enthusiast.
I am planning to return to <country/region> several time over the next few years for the said purposes: holiday/pleasure, visiting friends, as well as <optional: business reason>. In light of this, it would save me a great amount of time and effort if I were able to procure a longer term / multiple visa rather than have to apply each time a trip is scheduled.
I would greatly appreciate your consideration on this matter. Please do not hesitate to contact me for any questions via e-mail (<insert e-mail>) or mobile (<insert mobile no.>.
<Full Name and Signature>