Hello Veronica
You might be interested to read our latest guide about using the
online planning portal.
The advice there says:
Planning permission is not normally required for repairing, fitting or replacing doors and windows (including double glazing).
However, if the building is listed or is in a conservation area (or other designated area) you should consult with your local planning authority.
Also, if you are a leaseholder, you may first need to get permission from your landlord or management company.