Los datos de la tarjeta no reemplazan el factor de autenticación.

Because the subject is Los datos de la tarjeta, and the head noun there is datos, which is plural.

So the agreement works like this:

• los datos = plural
• reemplazan = they replace

Even though de la tarjeta comes in the middle, it does not control the verb. The verb agrees with datos, not with tarjeta.

So:

• Los datos ... reemplazan = correct
• Los datos ... reemplaza = incorrect

In this kind of context, datos usually means details, data, or information.

With de la tarjeta, los datos de la tarjeta most naturally means:

• the card details
• the card data
• the information from/on the card

A native English speaker may expect data to feel uncountable, but in Spanish dato is a countable noun, and datos is the normal plural form.

Examples:

• un dato = one piece of information / one datum
• los datos = the data / the details

De la tarjeta means of the card or more naturally in English card-related / from the card.

It tells you what kind of datos these are:

• los datos = the data/details
• los datos de la tarjeta = the card data/details

This is a very common Spanish structure:

• el número de teléfono = the phone number
• la contraseña del usuario = the user's password
• los datos de la tarjeta = the card details

Spanish often uses de where English might use apostrophe 's or a noun used as an adjective.

Spanish uses definite articles much more often than English.

So de la tarjeta is perfectly natural, even where English might simply say:

• card details
• card data

Spanish prefers:

• los datos de la tarjeta

rather than a bare noun like de tarjeta, which would usually sound incomplete or less natural here.

In standard Spanish, simple negation is formed by putting no directly before the conjugated verb.

So:

• reemplazan = they replace
• no reemplazan = they do not replace

This is the normal pattern:

• No entiendo. = I do not understand.
• No funciona. = It does not work.
• Los datos de la tarjeta no reemplazan el factor de autenticación.

English uses do not, but Spanish usually just uses no before the verb.

It is the direct object of reemplazan.

In other words, it is the thing being replaced:

• Los datos de la tarjeta = subject
• no reemplazan = verb
• el factor de autenticación = direct object

So the structure is:

[Subject] + [no + verb] + [direct object]

Because reemplazar takes a direct object, there is no preposition before el factor.

Because factor is a masculine noun in Spanish:

• el factor
• un factor

So you say:

• el factor de autenticación

This is true even though some English speakers may not have a strong feeling for grammatical gender with a word like factor.

De autenticación means of authentication or, more naturally in English, authentication used as a modifier.

So:

• el factor = the factor
• el factor de autenticación = the authentication factor

Spanish often links nouns with de where English puts one noun directly before another.

Compare:

• sistema de seguridad = security system
• código de acceso = access code
• factor de autenticación = authentication factor

So this is a very normal Spanish noun pattern.

Yes, in many contexts sustituir and reemplazar are close in meaning.

So you could say:

• Los datos de la tarjeta no sustituyen el factor de autenticación.

That would also mean the card details do not replace the authentication factor.

However, reemplazar is very common in technical and formal contexts, and it fits well here. Depending on the exact register, one verb may sound slightly more natural than the other, but both are grammatically fine.

Not here. Reemplazar normally takes a direct object without a preposition.

So:

• reemplazar algo = to replace something

That is why we get:

• reemplazan el factor de autenticación

not:

• reemplazan al factor de autenticación

You may sometimes see reemplazar a alguien when a person is being replaced, because Spanish can use the personal a with people:

• Van a reemplazar al director. = They are going to replace the director.

But with a thing like factor, no a is needed.

The written accent shows the stress: autenticación.

Without going too deep into spelling rules, the stress falls on the final syllable:

• au-ten-ti-ca-ción

The accent is necessary because words ending in -n are normally stressed differently unless marked.

Also, the ending -ción is extremely common in Spanish and often corresponds to English -tion:

• información = information
• autenticación = authentication
• validación = validation

In standard peninsular Spanish:

• reemplazan is roughly rre-em-pla-than in much of Spain, because z is often pronounced like the th in think
• autenticación is roughly au-ten-ti-ka-thyon in much of Spain

A few useful pronunciation points:

• r at the start of a word is a stronger r
• z in most of Spain sounds like th in think
• ción sounds roughly like thyon in Spain, or syon in much of Latin America

So a Spain learner should be aware of that z / c pronunciation difference.

Yes. Reemplazan is the present indicative, third person plural.

In a sentence like this, the present tense is often used to state a general fact, rule, or principle:

• Los datos de la tarjeta no reemplazan el factor de autenticación.

So it does not necessarily mean they are not replacing it right now at this exact moment. It more naturally means:

• Card data/details do not count as a replacement for the authentication factor
• As a rule, card details do not replace the authentication factor

This is very common in instructions, policies, and technical writing.