How do I write a letter of invitation to get a visa for my mother?

Your mother would visit the US on a visitor's visa, which can be granted for a period of up to 6 months. The US immigration authorities are interested in ensuring that your mother has the financial means of sustaining herself during her visit to the US and that she would return to the Philippines prior to the expiration of her visitor's permit. Thus, the letter from your end should provide relevant information for the US authorities in the Philippines to make the desired decision.

Since you arrived in the US recently, we are assuming that you are neither a permanent US resident nor a US citizen, thus your husband, who is a US national, should write this letter. The letter should be addressed to the US consulate or US embassy in the Philippines. The letter from your husband should state the following:

    Purpose of the letter
    His name, social security number, and contact information (address, phone, and email)
    His current employment status and financial means (such as house, savings, tax status in good standing, and so on)
    His relationship with your mother
    The purpose and duration of your mother's visit
    A request for the grant of a visitor's visa for your mother
    A strong statement that he would provide all necessary finances to meet all financial needs of your mother during her stay in the US
    An offer to provide any further information that the US authorities may need

This letter should be sent to your mother, who can then take it to the nearest US consulate or the US embassy in the Philippines. There is no guarantee that this letter would be sufficient, but if the US authorities need further information or guarantees, they would advise your mother accordingly. You can then take appropriate actions. One critical item: it is incumbent upon your mother to convince the local US authorities that she will return to the Philippines after her visit to the US.