How customizable? 

It's highly customizable but will take some time to learn how to use it most effectively. 

Podio and other CRM’s can be super customizable, so DO NOT keep yourself from completing revenue generating activities attempting to customize your CRM.

You will also find Construction Management software built specifically for homebuilders and remodelers like BuilderTrend & Co-Construct.Podio, AirTable or SmartSheet could also be a good solution because they are very customizable, but will take some work to get up and running.Here's a summary of other products you might want to consider for project management below:General Business Task ManagementTrello/Zoho Projects/Basecamp/Workflow - Feature-rich project management software that includes Tasks, Gantt scheduling, calendars, project forums, document storage & team collaboration tools.  

Is it customizable? 

It is very customizable and powerful.

@Joyce Williams You can find those on the Internet customizable by state and purpose.

They provide several features such as online lease signing, like you mentioned, along with customizable options to set up your lease templates.

This is customizable.

Also there is a huge selection of customizable templates that you can use to build a site.