First You need an attractive domain name. Many names are already taken, but there are still many available.
Second You need a website. You can find a web template for Your website. These are cheap. You need to have at least HTML coding experience to run this template as a website. You need to update it with the texts and images, prices, etc.
Third You need Metatrader Trade Copier Software. This is what Forex traders are looking for these days, a Forex Signal Service with autotrading. No one can sit in from of computer all day. So autotrading is a must to offer on Your website.
One team of programmers offer all solutions to start your signal service. This team of Metatrader MQL programmers have all the tools you need. They can help you start a website with your chosen web template. They can include PayPal payment buttons on your website and make the website run independently. Trade copier software is offered on their website. This means that when you will trade your account, your customers will get exact same trades as you run. You can even run some ea on your trading platform and trade copier will copy all these trades to your clients platforms. Trade copier software can be used on 100s even 1000s client platforms at the same time.
This is much better than to sell your profitable trading strategy or profitable expert advisor (EA) online. Imagine to have 100 clients with monthly payment of 100$ each, that is 100 x 100 = 10,000$ USD every month.