An independent copywriter can be someone who writes content or texts at the request. The word "freelance" indicates that they are an independent contractor, typically performing clearly-bounded copywriting assignments or commissions on an ad-hoc basis for a variety of clients.
"Copywriter" is a loosely defined term since copywriting is often a broad range of tasks that are more clearly defined in other fields including writing or rewriting, structuring planning editing, copy-editing with other professionals like web designers and graphic designers. If you are looking for freelance copywriting services in UK, then you can browse the web.
Image Source: Google
The majority of copywriters have their own websites, usually optimized for search engines so that they are able to attract users who type in keywords like "copywriter" or "freelance copywriter'.
After contact has been established the freelance copywriter will meet with the client in order to determine the type of copywriting needed. The majority of copywriters charge per day, though some might be willing to charge per hour or per word, or a thousand words.
Most important will be the wish to satisfy the client by going into the writing, not getting caught up in negotiations. In any event, sending an email from clients to a professional copywriter with explicit permission to move forward is typically the base for the copywriter to get started.