After reading this Sorlock guide and a further discussion in the comments about this topic, it's still unclear to me if the Voice of the Chain Master invocation lifts the requirement of spending an action to perceive through the familiar's senses.
The relevant part of the find familiar spell says:
While your familiar is within 100 feet of you, you can communicate with it telepathically. Additionally, as an action, you can see through your familiar's eyes and hear what it hears until the start of your next turn, gaining the benefits of any special senses that the familiar has. During this time, you are deaf and blind with regard to your own senses.
The warlock's Voice of the Chain Master eldritch invocation says, in part:
You can communicate telepathically with your familiar and perceive through your familiar’s senses as long as you are on the same plane of existence.
They invoke an explanation from Jeremy Crawford which, to me, doesn't clarify anything at all:
Voice of the Chain Master enhances the find familiar spell, which otherwise works as written for the warlock.
To me, "enhances the find familiar spell" could either mean solely that it increases the range at which you can perceive through the familiar's senses (or communicate telepathically), or that it both enhances the range and also removes the need to use your action to perceive through its senses. But again, this depends on how you read it.
Does Voice of the Chain Master remove the action usage requirement from find familiar? How are you arriving at that answer?
Best Answer
The invocation does only exactly what it says it does
As you quoted, the warlock's Voice of the Chain Master eldritch invocation says:
And, as Jeremy Crawford says, this is an enhancement to the general rule for familiars. The fact that you can now communicate telepathically with your familiar, and perceive through their senses, as long as they are are on the same plane as you, is an enhancement. No one would take the invocation if it wasn't.
This 'invocation', only makes sense as being an actual enhancement if both of these abilities were previously limited somehow by range.
The find familar spell states:
The range limitation on telepathic communication is 100 feet - so now being able to communicate with your familiar, across any distance, while they're on the same plane is a clearly a big buff.
The find familiar spell text doesn't make the range of the action to perceive through your familiar's senses so obvious. However, the eldritch invocation tell us that being able to take that action across any distance, while on the same plane is considered to be a buff - so it must also be range limited somehow.
With no other range stated in the spell, the only reasonable explanation is that the ability to perceive through your familiar's senses should be considered a subset of your ability to communicate telepathically with your familiar generally, and so normally falls under the same range retstriction - 100 feet.
This argument is strengthened when you consider that the spell text allowing the perceiving action begins with the word 'Additionally'. In plain English that normally means that this sentence relates closely and refers to the previous sentence, in some way. It's not meant to be interpreted as an unrelated point.
In conclusion, the invocation does not allow you to perceive through your familiar's senses without the use of an action. If it did, then it would say so - remember, in D&D 5e there are no secret rules. It allows you to communicate telepathically with your familiar and perceive through your familiar’s senses as long as you are on the same plane of existence. In order for these both to be things you could not otherwise do, without this invocation, they must normally both be range limited.
See also: What is the range limit on seeing through a familiar's eyes?