I worked in U.S. previously on H-1B visa for 3 years. Now, an international company in U.S. wants to hire me as a system engineer for a job needed to travel around the world in different agencies. If it is possible, please provide me with L-1 visa application procedure, such as documents needed and the initial stage.

For L-1 visa application, the petitioning U.S. organization needs to show that it is a branch, subsidiary, or affiliate of an overseas company in which the person to be sponsored has been working during one of the past three years in an executive, managerial, or specialized knowledge position. The application required forms are form I-129 petition for a nonimmigrant worker, and form I-129L classification supplement to form I-129. 

The materials accompanying an L-1 visa application for an established company can include annual reports, proof of affiliation, stock share certificates, and a company letter describing the company, the position to be fulfilled, and the position that the beneficiary has or is presently fulfilling in the overseas organization. 

If the organization is sufficiently large, it can obtain a blanket L-1 petition approval from the USCIS service center, and only file further paperwork at the consulates for its employees rather than having each petition approved by the USCIS.