Question – I am a US citizen thinking about bringing my mother

I am a US citizen thinking about bringing my mother to the USA. If I start the application process here in the US, will mother be allowed to enter on a tourist visa and stay will be and then go back to her country of residence for her interview? Will her tourist visa be automatically suspended while she is getting an immigrant visa?

Question – I ‘m the petitioner and sponsor for my wife my

I’m the petitioner and sponsor for my wife. my income was very low. I fill just one form i-864. should i find someone to help me in financial because my income is low. i have one friend. he have good income. he have to fill for me I-864 or I-864a.
which form? please?