I-94 clarification

[mummadis]

My Mother-in-law has a 10 year multi-entry visa, but when she came to visit us this month , the I-94 stamping was given only for 2 months till November.

Can she stay longer (for two more months) without filing for extension again??

I not, for how many more months can i file extension??

[taco]

She can only stay legally till the date on the I-94.

To stay more, file for an extension. But remember, if the extension
is denied and she has already stayed over the date on I-94, her visa
will become automatically cancelled. And she will have to apply for a new
visa.