The B-2 visa facilitates short-term travel to the United States by foreign nationals for non-business purposes such as tourism, family visits, and medical treatment.

[Overview of content]

1. Visa definitions
2. Scope of lawful activities
3. Application Requirements
4. processing process
5. special specification

I. The nature of visas

The B-2 visa is a nonimmigrant visa used for short-term travel to the United States for non-business activities. Its basic characteristics include:

• call: General 6-month stay in the U.S., renewable up to once, depending on circumstances.
• Not allowed to take up employment: May not work or receive remuneration in the United States
• multifarious uses: For travel, family visits, medical treatment, cultural events, etc.

II. Scope of lawful activities

1. Travel and tourism: visits to places of interest, national parks, city tours, etc. (no part-time work or internships)
2. Visiting Friends and Relatives: Visiting relatives, friends or family in the United States (may not receive U.S. financial assistance for schooling)
3. Medical treatment: short-term travel to the U.S. for medical services (medical records and letter of acceptance from the U.S. hospital are required).
4. Rest and recuperation vacations: short-term recuperation in the United States after a long period of stress (all expenses must be borne at one's own expense).
5. Accompanying family members: Accompanying other visa holders (e.g. F1/J1 spouses) for a short period of time (without independent work/study authorization).

III. Five core requirements

Visa officers usually examine the applicant's qualifications in the following five areas::

• Clear purpose of visit: itinerary, hotel reservation, invitation letter from relatives and other supporting materials should be submitted
• Sufficient financial means: proof of sufficient funds to cover all expenses while in the U.S. ($6,000 or more is usually recommended)
• Binding to return: need to demonstrate the applicant's stable occupation, family, assets or intention to reside permanently in the place of origin
• Good immigration record: avoid a history of detention or other visa violations
• Proof of non-immigrant orientation: B2 visas must show that they will leave the country at the end of the visit.

IV. Six-step application process

1. Define the purpose of the visit: tourism, family visits, medical treatment, etc.

2. Preparation of documents: invitation letter (e.g., for family visits), travel itinerary, proof of financial resources, etc.

3. Completion of Form DS-160: online non-immigrant visa application form

4. Payment of visa fees

5. Make an appointment and attend the interview: bring the following core documents:

• Original passport (valid for at least 6 months)
• DS-160 Confirmation Page and Payment Voucher
• Travel plan/letter of invitation/certificate of medical history (depending on the purpose of the visit)
• Documents related to the binding nature of funds and repatriation (e.g. bank statements, proof of real estate)

6. Entry with visa: Customs officials at the time of entry determine the actual length of stay and issue an I-94 record. 

V. Key considerations

Visa and Length of Stay Difference:

• Visa validity: usually 1, 5 or 10 years (multiple entries)
• Single stay: normally 6 months, with extensions or reductions granted at the discretion of the immigration officer.

Extensions and Changes:

• B-2s may apply to USCIS for one extension, but must be filed before the I-94 expires
• B-2 may not be directly converted to F-1, H-1B, etc., but must be converted through the formal process.

Common Misconceptions:

• B-2 is not permitted to engage in any form of employment or internship in the U.S.
• B-2 is not suitable for long-term accompanying or caring for a sick person, and other visa categories should be considered if the purpose of the stay is long term.
• Be careful when using B-2 for child birth or schooling, it may affect subsequent visa applications.

Professional Advice:

• Visa for visiting relatives: the invitation letter should state the relationship, purpose of visit and itinerary, and indicate the party who will bear the expenses.
• Medical Visa: Diagnostic certificates, treatment plans and cost estimates from U.S. hospitals must be prepared in advance.
• Interview performance: Answers should be concise and clear, demonstrating the temporary nature of the visit and the desire to return to the country.
• Application Timing: It is recommended that applications be prepared and submitted 2-3 months prior to the planned departure date.