You'll have a week to think about whether or not you want to accept the invitation. The due date will be communicated to you in the invitation. You will have a total of twenty days to submit an online application for a work permit, beginning on the day and time that you accept the invitation.

In order to say yes to the invitation:

In your account, navigate to the area labeled "Continue my profile / application, not yet submitted." Once there, locate the application labeled "Work permit," and then click the button labeled "Start application."
If you do not react within the specified time in the invitation, it will be considered that you declined the offer. Before you may be considered for future invites, you will need to resubmit a new IEC profile and go through the process of getting approved back into the pool if it ever becomes invalid.

You are required to submit an application for a work visa as soon as you have accepted your invitation. You are going to be required to provide evidence that supports the information that you included in your International Experience Canada (IEC) profile. You'll also need to supply additional information about your history and the kind of job you want to conduct in Canada in order to satisfy this requirement.

a refusal to accept an offer to apply
If you turn down an invitation, your name will remain in the IEC candidate pool (provided that you continue to meet the requirements) so that it can be considered during subsequent rounds of invitations.

If you decide to refuse an invitation, doing so will not have any impact on the invites that will be sent to you in the future.

In order to refuse the invitation:

In your account, navigate to the area labeled "Continue my profile / application, not yet filed." Once there, locate the application titled "Work permit," and then select the button labeled "Decline application."
If you do not answer to an invitation by the deadline that is specified on the invitation, the invitation will be considered declined. Before you may be considered for future invites, you will need to resubmit a new IEC profile and go through the process of getting it approved into the pool if it becomes out of date.

Applicants from a number of different pools
If you are entered into more than one pool and you are extended an invitation to apply for one category, you will not be considered for selection from any other pool unless the following conditions are met:

either you do not accept the Invitation to Apply or you have already filed your application for a work permit, but we have decided not to accept it.
In the event that you do not accept the invitation or that we do not approve your request for a work permit, your profile will become active once again, and you may be sent another Invitation to Apply.

Included in your application for a work permit are the supporting documents.
If you are accepted into an IEC pool, you should think about getting your supporting papers ready because it may take some time to prepare some of them (for example, the certificate(s) of good conduct from the police). Candidates currently in the pool will get invites to apply at regular intervals. If you accept an Invitation to Apply, you will only have twenty days to finish and submit your application for a work permit, together with all of the supporting documentation. If you do not complete and submit your application within this time period, your application will be denied. It would be much simpler to submit an application within the allotted 20 days if these papers may be prepared in advance.

You have the option of remaining in an IEC pool if you are not extended an invitation to apply:

until we remove all profiles from the pools at the conclusion of the season, or until it is determined that you are no longer qualified for IEC.
Before the end of the season, there will be a shortage of slots available in some categories. In the event that this does place, we will immediately suspend accepting new profiles for that pool. There is still a chance that you may receive an invitation to submit an application for another category, even if your profile is already in the pool for that category. If you wish to add a profile to a different pool, you must first withdraw the profile you've already submitted and then add a new one.

You will be informed through your account that the pools are closed once we have completed the process of closing them.

The swimming pools will be closed at the conclusion of each season for a period of at least two weeks while we get ready for the following season.

If you are still interested in joining the International Experience Canada program so that you may travel and work there, you will need to create a new profile and submit it when the application process for the following season starts. When you first begin, you'll have a total of sixty days to finish the profile. If you continue to satisfy the essential entrance requirements, you will be issued a new IEC profile number. You will be required to create a new account if you do not submit a new profile within the allotted 60 days.