Define your rate codes (for example "Senior Consultant" or "Metallurgical Engineer 2") based on how you show your clients a "rate card" with default or initial rates under Master Billing Rates. Then open your employee via manage > hr > people and click on the pencil icon to open the JOB tab. Select the appropriate rate code for your employee from the drop-down list of master rates as highlighted above. The other JOB tab fields are explained here.

Assigning a master rate code to an employee causes that rate to default into projects when this employee is assigned, unless a project-specific rate has been previously assigned. You can always edit each employee's billing rate in a specific project, as mentioned below.

Some companies does not operate with a standard rate card or rate sheet for time & materials / hourly work. In this case it is possible to assign individual rates to individual employees. To do this on the same JOB tab in employee admin check the "individual billing rate" box to the right of their rate code, as highlighted above. Instead of selecting a rate code you can now enter the specific rate applied to this individual's billing rate, with currency and per-time unit in the proper format e.g. "400 USD/day" or "75 EUR/hour".

Even though this individual has their own billing rate it is still possible to charge them out at different rates in different clients or projects, by maintaining project specific rates as mentioned below.

After you have assigned your project resources with a default rate code or individual rate in employee admin JOB tab (as outlined above) you can adjust or modify their rate on individual projects, to allow the same person to charge a different rate to different clients or for different kinds of work. Depending on your project's pricing strategy, edit the individual's billing rate in the project RESOURCES tab (as shown above) or in the project RATES tab. The rates tab allows you define multiple rates for an individual within a project based on for example service.

Notes:

1. Your system administrator can allow or prevent project specific rates based on your project type settings
2. Not only can you modify project specific billing rates but you can also assign a project specific rate code, for example because Fred Jones who is normally a senior consultant is acting as (and being billed as) a project manager on one specific engagement
3. You must assign a rate code or individual billing rate as a default in employee admin JOB tab before you can maintain project-specific rates or rate codes.

Refer to this link for more background on setting prices on projects.

If you have client-specific rate cards and a very large number of projects for each client, it can become tedious to edit the rates to the client-specific rates on each and every client project. In this case you can define a special product or service for this client and maintain default rates by rate code in that service. To do this open or create the service and click on the + button in the billing rates code list in the SERVICE tab, as shown in the image above.

Service-based rates will default in the project for resources when the pricing strategy is by service and resource. You still have the option to edit rates on individual projects (unless locked-out by your project type settings) but default rates will be client-specific because of a client-specific product or service.