Your professional business website is your shop, your consulting room, your display case. The following are absolutely critical to success (in no particular order):
1) Fast loading - buyers are very, very impatient
2) Easy navigation - visitors must find what they seek with a minimum number of clicks right through to the buying process
3) Beautiful, clear, branding - the identity of your business
4) Trust - your website must contain the element that say subconsciously - 'you can trust us'
5) Optimized On-Site SEO - if the back-end data on your site isn't right then ranking on Google will be much, much harder
6) Fully mobile optimized
7) Secure - and visibly secure to visitors
8) Backed up and supported for minimum downtime
9) Able to support your business model - no matter whether you are selling professional services, products or courses or whatever. This means integration with modern selling tools such as Zoom (consulting), payment channels such as PayPal and credit Cards, email facilities, chatbots and more.
A professional business website doesn't just look good - it performs, and converts visitors to buyers.