I have 8 years experience in sales and marketing, Now i like to get into SAP world as a functional consultant. can you please guide me like what kind of certifications can i do and i live in London is there any good firm which will provide training and help for certifications. is it possible to write the certifications exam without training if i managed to get the materials and study myself,
You can get training details from https://training.sap.com/us/en/. The link is for the US but you should be able to change the location.
Going from Sales and Marketing to SAP functional consultant seems to be a drastic change to me that might not have very many shared skill sets. You can register for trainings in a specific area to prep for a certification. I'm not sure if you can take the exam without attending the associated course I think it varies by region.
Within UK, you do not have any prerequisite to undergo a training. You can contact local SAP Education team, they will advice you for registering the examination.
You can find the course details here.
Mostly, you will find exams on a weekly basis. Following is the schedule:
Please let me know if you have further specific questions.
Thanks and Regards,