From the gov.uk site:
If you’re an office holder
If you are an office holder who is remunerated by PAYE then you can be furloughed and receive support through this scheme. The furlough, and any ongoing payment during furlough, will need to be agreed between you and the party who operates PAYE on the income they receive for holding their office. Where you are a company director or member of a Limited Liability Partnership (LLP), the furlough arrangements should be adopted formally as a decision of the company or LLP.
If you’re a company director
As office holders, salaried company directors are eligible to be furloughed and receive support through this scheme. Company directors owe duties to their company which are set out in the Companies Act 2006. Where a company (acting through its board of directors) considers that it is in compliance with the statutory duties of one or more of its individual salaried directors, the board can decide that such directors should be furloughed.
Where furloughed directors need to carry out particular duties to fulfil the statutory obligations they owe to their company, they may do so provided they do no more than would be judged reasonably necessary for the purposes, i.e. they should not do work of a kind they would carry out in normal circumstances to generate commercial revenue or provides services to or on behalf of their company.
This also applies to salaried individuals who are directors of their own personal service company (PSC).
Company directors with an annual pay period
Those paid annually are eligible to claim, as long as they meet the relevant conditions. This includes being notified to HMRC on an RTI submission on or before 19 March 2020, which relates to a payment of earnings in the 19/20 tax year. The requirement for there to be payment of earnings in the 19/20 tax year applies for any employee being claimed for under the scheme, irrespective of how frequently they are paid (e.g. weekly, fortnightly or monthly). This will be relevant for those on an annual pay period if the last payment notified to RTI was before 5 April 2019 and no further payments were notified until after 19 March 2020.
https://www.gov.uk/guidance/check-if-you-could-be-covered-by-the-coronavirus-job-retention-scheme