Consider these examples:
You should be more careful in future.
In the future we plan to make significant investments in Romania and Bulgaria.
In the first example “in future” means “from now on and always”. It is often used in the context of changing habits or behaviour, and may form part of a reprimand (such as in the above example).
In the second example “in the future” means “at/from some future point in time”.
“In future” is used mainly in British English. Speakers of US English may not be familiar with it. They tend to use “in the future” for both meanings.
He reassured shareholders that the bank would in future focus on services for individuals and small businesses.
Trade relations between member countries will in future be conducted primarily on a bilateral basis.
He said that similar treaties with Latvia and Lithuania would be concluded in the future.
I would like to know whether you think the project will be profitable in the future.
Here are a couple of similar phrases that work like “in the future”:
We expect a bill on this subject to be submitted to Parliament in the near future.
I’m looking forward to meeting you again in the not-too-distant future.
You should be aware that native speakers’ use of these terms may not always conform to these rules. In particular, British English speakers may use “in future” when they should use “in the future”.