The L1 Visa is a temporary non-immigrant visa designed to facilitate the transfer of foreign workers to the US offices of their employer. It's available to employees of multinational companies with branches both overseas and in the US. Additionally, the L1 Visa allows foreign companies without a US office to send an executive or manager to establish one.

There are two categories of L1 Visa:

1. 1A Visa: This is for executive managers.
2. 1B Visa: This is for employees with specialized knowledge.

To qualify for the visa, employees must have worked for the company for at least one continuous year within the three years before their planned admission to the US. The visa permits employees to come to the US for a specific period and work for the same employer as in their home country but in a US office. If someone wishes to work for a new employer in the US, they should consider applying for an employment-based green card.

The L1 visa lets workers from foreign countries move to the United States to work for a company that operates both in the US and abroad. You can stay for up to seven years.

To get an L1 visa, you need to have worked for the foreign company for at least one year straight in the last three years. The US company must be related to the foreign company, like being its parent, subsidiary, affiliate, or branch.

For L1A visas, managers and executives need to have supervisory responsibilities over staff or key functions within the company. L1B visas are for employees who have expertise in the company's products, services, or procedures.

When you first get an L-1 visa, you can stay in the US for up to three years. You can ask to stay longer, up to seven years for L-1A visas or five years for L-1B visas.

The L-1 visa is commonly used by multinational companies to move their employees to the US and continue doing business there.

After you finish the maximum allowed time with the L-1 visa, you must follow immigration rules before applying for a different visa status.