A visa letter of invitation is a document that is often used to help a foreign citizen gain a tourist visa to enter another country.  The letter is an invitation to visit from a relative or close friend who is a citizen or permanent resident of the country.  The person issuing the invitation is often taking responsibility, including financial, for the foreigner for the duration of his visit.

Identification
A visa letter of invitation is an official document, often signed by the issuer in the presence of a notary public, that invites the receiver--a foreign citizen--to visit her.  In the letter, the issuer states her personal relationship with the visa applicant as well as the purpose for the visit.  It also often contains a guarantee that the issuer will be a host for the visitor and be responsible for his accommodation and travel expenses while in the country.

The person issuing the letter must also list her residence, as well as verification of her legal status in the country.
Significance
Although not always required as part of a visa application, a visa letter of invitation can often be a deciding factor in a government's decision to issue or not issue a visa.  The letter of invitation is proof a visa applicant has a legitimate visiting interest in the country and gives the government assurances that one of its citizens is taking responsibility for the foreign visitor.  Some countries--for example, Libya and Turkmenistan--require visa applicants to have a person (a host) issue a letter of invitation prior to issuing a tourist visa.  Also, the United States will require letters of invitation for visa applicants from counties with which they do not maintain diplomatic relationships.

Time Frame
The foreign citizen wishing to visit a country should contact his relative in that country, asking whether she will write a visa letter of invitation.  That letter, after being signed and notarized by the sponsor, should be sent to the visa applicant, who will then submit the letter with his application.  The length of time between submitting the application and being granted a visa will depend on the country, but at a minimum the visa letter of invitation writing process should begin 6 months before the visit.

Benefits
In addition to the main benefit of increasing the likelihood a visa application will be approved, a visa letter of invitation can help an applicant meet portions of the entry requirements.  For example, some countries require entrants have a return airplane ticket or a certain amount of money to enter the country.  If a visa applicant cannot meet these requirements, a sponsor's guarantee of money or assistance can usually help satisfy the requirements.
This is particularly the case when parents travel overseas to visit children who have immigrated to a country.  If the children are paying for the trip, this can be stated in the visa letter of invitation.

Warning
When submitted with a visa application, many countries consider a letter of invitation to be an official document.  If a person falsifies or misrepresents a person or their relationship for the purpose of helping a foreign citizen obtain an entry visa, she has broken the law.  Visa letters of invitation should only be written when the issuer has a genuine relationship with the person requesting it.

Thanks lets make use of this opportunity to educate others whatever we know about visa processing so as not to fall in the hand of fake visa processing agencies

Thats a wonderful information dude and really help those who are struggling for getting visa for any country.  nice information.  thanks

Thanks for the guidelines, This information will be useful when applying for visa in any country. It provide basic information to the tourist for travelling abroad.