Monthly cost from €150 for use of space in the home

Normally, you should enter all invoices related to that use as other costs with a fixed percentage of professional use (e.g. 20%). For council tax, you use the council tax assessment notice, and for electricity, gas, water, fire insurance, etc., you use the invoices from your suppliers. You enter each of these documents in the correct expense category and indicate the percentage of professional use.
Johan

Thank you, but the KI and, for example, the fire insurance and gas are in a different name, that of my husband. Does this have to be paid through my professional account or is this not a requirement?That depends. If you are self-employed in secondary occupation and you officially live together (married or cohabitation contract), it does not matter whose name the invoices are in if the house belongs to both of you. The house is insured and council tax is paid by its owners. You are one from those owners, so you can include that share in your expenses if your business is located in that house (not if your business is located at a other address). It does not matter to the tax authorities which account you use to pay this, because as a self-employed person in a secondary occupation, you form a single economic identity with yourself as a private individual. However, it is wise to keep a summary for yourself so that you pay as many of the costs you claim as possible from your professional account.