Hi Flex Xuan,
'Call From' and 'Call To' are party list type field, they will be saved as separate activityparty entity records.
In other word, there will be two activityparty records for a phone call record.
We should instead expand activityid_phonecall property to show fields of related phone call record.
e.g:
display 'Call From' and 'Call To' field of a specific phone call record:
var entityId = 'xxxx'; // phone call record id
Xrm.WebApi.retrieveMultipleRecords("activityparty", "?$expand=activityid_phonecall($select=subject)&$filter=_activityid_value eq " entityId
" and (participationtypemask eq 1 or participationtypemask eq 2)&$select=_partyid_value,_activityid_value,participationtypemask").then(
function success(result) {
for (var item in result.entities) {
if (result.entities[item]["participationtypemask"] === 1) {
console.log("Phone call activity: " result.entities[item]["_activityid_value"] ", Subject: " result.entities[item]["activityid_phonecall"]["subject"] ", Call From: " result.entities[item]["_partyid_value@OData.Community.Display.V1.FormattedValue"]);
} else if (result.entities[item]["participationtypemask"] === 2) {
console.log("Phone call activity: " result.entities[item]["_activityid_value"] ", Subject: " result.entities[item]["activityid_phonecall"]["subject"] ", Call To: " result.entities[item]["_partyid_value@OData.Community.Display.V1.FormattedValue"]);
}
}
},
function (error) {
console.log(error.message);
}
);

If activity entity is "PhoneCall", then when participationtypemask field of activityparty record equals to 1, it stands for Call From,
when the field equals to 2, it stands for Call To.
In a word, we should retrieve phone call based on activityparty entity.
Furthermore, we can also retrieve "From" and "To" fields of Email based on it.
Here are some helpful links about your question:
1. participationtypemask code meaning for different activity entities:
https://docs.microsoft.com/en-us/dynamics365/customerengagement/on-premises/developer/activityparty-entity
2. available properties to expand of activityparty entity:
https://docs.microsoft.com/en-us/dynamics365/customer-engagement/web-api/activityparty?view=dynamics-ce-odata-9#single-valued-navigation-properties
3. a tutorial about the topic:
https://promx.net/en/2020/01/how-to-retrieve-an-activity-party-list-in-microsoft-dynamics-365-using-web-api/
Regards,
Clofly