Good employment practice is for employers to ask you if you need any reasonable adjustments for any part of the application process, but this does not always happen. This is often because employers don’t know they should offer to make adjustments, rather than any attempt to avoid making them. If it helps, you can refer the company to employer information about reasonable adjustments in our section for employers.
You can ask for reasonable adjustments even if they are not offered to you, but you may have to declare that you have a disability. There is more about telling an employer that you are autistic in our section on applying for work. Your objective is to make the process accessible for you and your personal needs.