Learn Hardcore Japanese: haha ha ginkou de okane wo orosimasu.

は marks the topic of the sentence—it tells us that “as for my mother…” you’re going to say something about her. In contrast, が would mark the subject and often introduce new information or emphasise who does the action.

Using 母が銀行でお金をおろします shifts focus to “it’s my mother (not someone else) who withdraws money.”
Using 母は銀行でお金をおろします sets up “mother” as the topic and then tells us what she does.

What role does で play in 銀行で?

The particle で indicates the location where an action takes place. Here, 銀行で means “at the bank” (the place where the withdrawing happens).

Why is the object お金 followed by を?

を marks お金 as the direct object of the verb. It shows WHAT is being withdrawn.

What does the verb おろします mean?

おろします is the polite non-past form of the verb 下ろす, which means “to withdraw” (specifically money from a bank account). You can also use 引き出します, which has the same meaning in this context.

Why is the verb in the -ます form (おろします) instead of the plain form (おろす)?

The -ます form is Polite Speech (丁寧語). It’s used in formal or respectful contexts. The plain form おろす is casual and used among friends or in writing like diaries.

Can I say 銀行からお金をおろします instead of 銀行でお金をおろします?

Yes.

から focuses on the source—the bank—from which the money comes.
で focuses on the place where the action occurs.
Both are grammatically correct; just the nuance shifts slightly.

Could I use 母が銀行でお金をおろします instead of 母は銀行でお金をおろします?

Yes.

母が銀行でお金をおろします emphasises who is doing it (“My mother is the one who withdraws money”).
母は銀行でお金をおろします treats “mother” as the topic and then states what she does. Both are valid but serve different emphatic purposes.