The order will protect religious group against the Johnson amendment, legislation which bans non-profit organisations from openly supporting or opposing political candidates.
Pastors to speak from the pulpit about politics have previously risked losing their tax-exempt status.
The new order will instruct tax officials to "exercise maximum enforcement discretion to alleviate the burden of the Johnson amendment".
According to a senior White House official quoted by AFP, the executive order won't give specific details concerning what such relief wil be.
The order will also make it easier for business owners to operate according to their religious beliefs when it comes to providing health insurance schemes for employees.
They will be given the right to refuse to pay for contraceptive devices and services - a move which undermines the Affordable Care Act introduced under the Obama administration.
Mr Trump will introduce the order to mark the National Day of Prayer.
Rights campaigners fear the move will effectively legalize discrimination, while some conservative religious leaders had called for stronger measures to be taken.