If something happens often, it happens many times.
position in clause
• If there is no auxiliary verb, you put often in front of the verb, unless the verb is be. If the verb is be, you put often after it.
We often get very cold winters here.
They were often hungry.
• If there is an auxiliary verb, you put often after it.
She has often written about human rights.
• If there is more than one auxiliary verb, you put often after the first one.
The idea had often been discussed.
• If a sentence is fairly short, you can put often at the end of it.
He's in London often.
• In writing, often is sometimes put at the beginning of a long sentence.
Often in the evening the little girl would be sitting at my knee while I held the baby.
Don't use ‘often’ to talk about something that happens several times within a short period of time. Don't say, for example, ‘I often phoned her yesterday’. You say ‘I phoned her several times yesterday’ or ‘I kept phoning her yesterday’.
That fear was expressed several times last week.
Rather than correct her, I kept trying to change the subject. Adverbs and adverbials (for a graded list of words used to indicate frequency)
other uses of ‘often’
You use often with how when you are asking about the number of times that something happens or happened.
How often do you need to weigh the baby?
How often have you done this programme?
Often can also be used for saying that something is done just once by many people, or that something is true about many people.
People often asked me why I didn't ride more during the trip.
Older people often catch this disease.