what do I fill in for scope 1 if I don't have my own vehicles

Without own vehicles, scope 1 is usually zero or close to zero

Scope 1 is the direct emissions of the company itself: combustion of fuel in own facilities or own vehicles, and any refrigerant leakage from own air conditioning or cooling systems, as set out in the GHG Protocol classification. No own vehicle fleet means that the item "fuel consumption vehicles" falls away. What remains: does the company have its own boiler or installation running on gas, propane or diesel, and are there own cooling installations with refrigerant that can leak. If not, then scope 1 is rightly zero or nearly zero — that is not an omission, that is the outcome for a company without its own sources of combustion.

Therefore do not automatically fill in "0" without reading the question itself: check whether there is an own heating installation running on fossil fuel, as that does count towards scope 1, even without vehicles. Leased cars and rented business cars registered in the company's name also fall under scope 1 if the company has operational control — "no own vehicle fleet" is therefore not automatically the same as "no vehicles in scope 1". Employees driving private cars for commuting, or transport by an external carrier, does not fall under scope 1 but under scope 3. Do not forget when filling in that scope 1 is separate from scope 2, indirect emissions from purchased electricity — this is a separate question with a different answer.

Based on: GHG Protocol and the VSME basic module

The scope classification comes from the GHG Protocol, which defines scope 1 as direct emissions from sources that are owned by or controlled by the reporting company. The EFRAG VSME standard requires in the basic module to report these three scopes separately, precisely because customers need them separately for their own supply chain. For a complete picture of how scope 1 relates to scope 2 and 3 in a single supply chain question, see the question about scope 1, 2 and 3 together.