Considering this, how early can I apply for visa extension?
You can extend at any time before your current permission to stay in the UK expires. If you're extending to stay with the same family member, you'll only get up to 28 days left on your current stay added to your new visa.
Secondly, how do I ask for a visa extension? If you want to extend your stay in the United States, you must file a request with U.S. Citizenship and Immigration Services (USCIS) on the Form I-539, Application to Extend/Change Nonimmigrant Status before your authorized stay expires.
Also, when should I extend my visa?
When to make a student visa extension in the UK
The immigration rules say that an application for permission to stay must be made no more than 3 months before the start date given in the new CAS document.
How much is spouse visa extension fee?
It costs £1033 to apply to extend your spouse visa. Other costs will also apply, such as the Immigration Health Surcharge and the fee to submit your biometric information.